Bugs, Complement, Hormones, Silkworm
by
0

The conjugate (10S,11S) JH diol phosphate is the product of a two-step enzymatic process: conversion of JH to JH diol and then addition of a phosphate group to C10

The conjugate (10S,11S) JH diol phosphate is the product of a two-step enzymatic process: conversion of JH to JH diol and then addition of a phosphate group to C10.

  • Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994
  • Reversed-phase liquid chromatographic separation of juvenile hormone and its metabolites, and its application for an in vivo juvenile hormone catabolism study in Manduca sexta. Anal. Biochem. 188, 394-397

The enzyme responsible for the phosphorylation of JH diol is JH diol kinase (JHDK), which was first characterized from the Malpighian tubules of early fifth instars of M. sexta.

  • Grieneisen, M.L., Kieckbusch, T.D., Dorman, G., Latli, B., Prestwich, G.D., Schooley, D.A., 1995
  • Characterization of the juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol phosphotransferase (JHDPT) from Manduca sexta Malpighian tubules. Arch. Insect Biochem. Physiol. 30, 255-270
  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  • Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890

The Malpighian tubule system is a type of excretory and osmoregulatory system found in some insects, myriapods, arachnids and tardigrades. The system consists of branching tubules extending from the alimentary canal that absorbs solutes, water, and wastes from the surrounding hemolymph. The wastes then are released from the organism in the form of solid nitrogenous compounds and calcium oxalate. The system is named after Marcello Malpighi, a seventeenth-century anatomist.

Malpighian tubules are slender tubes normally found in the posterior regions of arthropod alimentary canals. Each tubule consists of a single layer of cells that is closed off at the distal end with the proximal end joining the alimentary canal at the junction between the midgut and hindgut. Most tubules are normally highly convoluted. The number of tubules varies between species although most occur in multiples of two. Tubules are usually bathed in hemolymph and are in proximity to fat body tissue. They contain actin for structural support and microvilli for propulsion of substances along the tubules. Malpighian tubules in most insects also contain accessory musculature associated with the tubules which may function to mix the contents of the tubules or expose the tubules to more hemolymph. The insect orders, Dermaptera and Thysanoptera do not possess these muscles and Collembola and Hemiptera:Aphididae completely lack a Malpighian tubule system.

Pre-urine is formed in the tubules, when nitrogenous waste and electrolytes are transported through the tubule walls. Wastes such as urea and amino acids are thought to diffuse through the walls, while ions such as sodium and potassium are transported by active pump mechanisms. Water follows thereafter. The pre-urine, along with digested food, merge in the hindgut. At this time, uric acid precipitates out, and sodium and potassium ions are actively absorbed by the rectum, along with water via osmosis. Uric acid is left to mix with faeces, which are then excreted.

Complex cycling systems of Malpighian tubules have been described in other insect orders. Hemipteran insects use tubules that permit movement of solutes into the distal portion of the tubules while reabsorption of water and essential ions directly to the hemolymph occurs in the proximal portion and the rectum. Both Coleoptera and Lepidoptera use a cryptonephridial arrangement where the distal end of the tubules are embedded in fat tissue surrounding the rectum. Such an arrangement may serve to increase the efficiency of solute processing in the Malpighian tubules.

Although primarily involved in excretion and osmoregulation, Malpighian tubules have been modified in some insects to serve accessory functions. Larvae of all species in genus Arachnocampa use modified and swollen Malpighian tubules to produce a blue-green light attracting prey towards mucus-coated trap lines. In insects which feed on plant material containing noxious allelochemicals, Malpighian tubules also serve to rapidly excrete such compounds from the hemolymph. See also Cryptonephridium.

  • Green, L.B.S. (1979) The fine structure of the light organ of the New Zealand glow-worm Arachnocampa luminosa (Diptera: Mycetophilidae). Tissue and Cell 11: 457–465.
  • Gullan, P.J. and Cranston, P.S. (2000) The Insects: An Outline of Entomology. Blackwell Publishing UK ISBN 1-4051-1113-5
  • Romoser, W.S. and Stoffolano Jr., J.G. (1998) The Science of Entomology. McGraw-Hill Singapore ISBN 0-697-22848-7
  • Bradley, T.J. The excretory system: structure and physiology. In: Kerkut, G.A. and Gilbert, L.I. eds. Comprehensive insect physiology, biochemistry and pharmacology. Vol.4 Pergamon Press New York ISBN 0-08-030807-4 pp. 421–465

In insect anatomy, a cryptonephridium is a structure present in most larval Lepidoptera and in other insects (i.e., Coleoptera) inhabiting relatively arid environments. The Malpighian tubules are not free in the hemocele but are bound to the wall of the rectum by the perinephric membrane. This structure allows efficient resorption of water from diuresis and absorption of atmospheric water that is present in the hindgut as humidity. An adaptation for water conservation.

  • Wigglesworth, V.B. 1953. The Principles of Insect Physiology. 5th edition, E.P. Dutton & Co. Ltd., New York. p. 369.
  • Klowden, M.J. 2007. Physiological Systems in Insects. 2nd edition, Academic Press. p. 416

JHDK (EC 2.1.7.3) was discovered when an analysis of JH I metabolites in vivo yielded, in addition to the expected metabolites, a very polar JH I conjugate that was subsequently identified as JH I diol phosphate.

  • Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994

Maxwell et al. showed JHDK to contain 3 potential calcium binding sites, and a single ATP-Mg2+ binding site (p-loop).

Calcium-binding proteins are proteins that participate in calcium cell signaling pathways by binding to Ca2+, the calcium ion that plays an important role in many cellular processes. Calcium-binding proteins have specific domains that bind to calcium and are known to be heterogeneous. One of the functions of calcium binding proteins is to regulate the amount of free (unbound) Ca2+ in the cytosol of the cell. The cellular regulation of calcium is known as calcium homeostasis.

Many different calcium-binding proteins exist, with different cellular and tissue distribution and involvement in specific functions. Calcium binding proteins also serve an important physiological role for cells. The most ubiquitous Ca2+-sensing protein, found in all eukaryotic organisms including yeasts, is calmodulin. Intracellular storage and release of Ca2+ from the sarcoplasmic reticulum is associated with the high-capacity, low-affinity calcium-binding protein calsequestrin. Calretinin is another type of Calcium binding protein weighing 29kD. It is involved in cell signaling and shown to exist in neurons. This type of protein is also found in large quantities in malignant mesothelial cells, which can be easily differentiated from carcinomas. This differentiation is later applied for a diagnosis on ovarian stromal tumors. Also, another member of the EF-hand superfamily is the S100B protein, which regulates p53. P53 is known as a tumor suppressor protein and in this case acts as a transcriptional activator or repressor of numerous genes. S100B proteins are abundantly found in cancerous tumor cells causing them to be overexpressed, therefore making these proteins useful for classifying tumors. In addition, this explains why this protein can easily interact with p53 when transcriptional regulation takes place.

Calcium-binding proteins can be either intracellular and extracellular. Those that are intracellular can contain or lack a structural EF-hand domain. Extracellular calcium-binding proteins are classified into six groups. Since Ca (2+) is an important second messenger, it can act as an activator or inhibitor in gene transcription. Those that belong to the EF-hand superfamily such as Calmodulin and Calcineurin have been linked to transcription regulation. When levels of Ca(2+) increase in the cell, these members of the EF-hand superfamily regulate transcription indirectly by phosphorylating/dephosphorylating transcription factors.

Secretory calcium-binding phosphoprotein

The secretory calcium-binding phosphoprotein (SCPP) gene family consists of an ancient group of genes emerging around the same time as bony fish. SCPP genes are roughly divided into acidic and P/Q-rich types: the former mostly participates in bone and dentin formation, while the latter usually participate in enamel/enameloid formation. In mammals, P/Q-rich SCPP is also found in saliva and milk and includes unorthodox members such as MUC7 (a mucin) and casein. SCPP genes are recognized by exon structure rather than protein sequence.

With their role in signal transduction, calcium-binding proteins contribute to all aspects of the cell’s functioning, from homeostasis to learning and memory. For example, the neuron-specific calexcitin has been found to have an excitatory effect on neurons, and interacts with proteins that control the firing state of neurons, such as the voltage-dependent potassium channel.

Compartmentalization of calcium binding proteins such as calretinin and calbindin-28 kDa has been noted within cells, suggesting that these proteins perform distinct functions in localized calcium signaling. It also indicates that in addition to freely diffusing through the cytoplasm to attain a homogeneous distribution, calcium binding proteins can bind to cellular structures through interactions that are likely important for their functions.

See also

Proteins: carrier proteins
Cell signaling: calcium signaling and calcium metabolism

The modeled structure contains nine helices, one beta sheet, and 10 loops. JHDK is also present in the silkworm, where it also functions as homodimer. It lacks a JH response element; Li et al. (2005). It has a high degree of identity to M. sexta JHDK. Later Uno et al. (2007) characterized the A. mellifera enzyme in a proteomic study. It has 183 amino acid residues. More recently, Zeng et al. (2015) have characterized JHDK from Spodoptera litura. It also has 183 amino acid residues, just as does the B. mori enzyme. These enzymes all have high sequence similarity. The M. sexta enzyme contains 184 residues.

  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881

JHDK from M. sexta Malpighian tubules is a cytosolic protein composed of two identical subunits of 20 kDa, as determined by MS.

  • Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890

Gel filtration studies indicate it has a molecular mass of approximately 43 kDa. JHDK displays a Km in the nanomolar range for JH I diol, which is appropriate for an enzyme responsible for clearance of a hormone whose titers rarely exceeds 10 nM. Most significantly, the catalytic activity of JHDK parallels developmentally that of JHEH, a requisite if JH diol phosphate is a legitimate terminal metabolite. Analysis of the kcat/Km ratio for the diols of JH I, II, and III indicates that JH I diol is the preferred substrate, suggesting a preference for an ethyl group at the C7 position. JHDK requires both Mg2+ and ATP for activity.

  • Grieneisen, M.L., Kieckbusch, T.D., Dorman, G., Latli, B., Prestwich, G.D., Schooley, D.A., 1995

JHEH is a membrane associated protein, and by photoaffinity labeling has been shown to be a 50 kDA protein in Manduca sexta.

  • Touhara K, Soroker V, Prestwich GD (June 1994). “Photoaffinity labeling of juvenile hormone epoxide hydrolase and JH-binding proteins during ovarian and egg development in Manduca sexta”. Insect Biochemistry and Molecular Biology. 24 (6): 633–640. doi:10.1016/0965-1748(94)90100-7.

It has been noted by several that properties of JHEH are similar to those of animal microsomal epoxide hydrolase. Sequence alignments showed that the exact catalytic triad of the animal enzyme (Asp-226, Glu-403 and His-430) is present in JHEH. In addition, the X-ray structure of Bombyx mori JHEH was recently determined.

  • Harris SV, Thompson DM, Linderman RJ, Tomalski MD, Roe RM (1999). “Cloning and expression of a novel juvenile hormone-metabolizing epoxide hydrolase during larval-pupal metamorphosis of the cabbage looper, Trichoplusia ni”. Insect Mol. Biol. 8 (1): 85–96. doi:10.1046/j.1365-2583.1999.810085.x. PMID 9927177.
  • PDB: 4QLA​; Zhou K, Jia N, Hu C, Jiang YL, Yang JP, Chen Y, Li S, Li WF, Zhou CZ (2014). “Crystal structure of juvenile hormone epoxide hydrolase from the silkworm Bombyx mori”. Proteins. 82 (11): 3224–9. doi:10.1002/prot.24676. PMID25143157.

Characterization of the juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol phosphotransferase (JHDPT) from Manduca sexta Malpighian tubules. Arch. Insect Biochem. Physiol. 30, 255-270), although excess Mg2+ and Ca2+ inhibit its activity.

  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  • Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890

The specificity of JHDK for JH I diol is relatively high, considering the multitude of potential phosphate acceptor groups present in a cell. The enzyme does not recognize methyl geranoate diol (one isoprenyl unit shorter than JH) nor methyl geranylgeranoate diol (one isoprenyl group longer than JH), yet it does recognize JH I ethyl ester diol. It also recognizes both JH diol enantiomers, indicating that the absolute stereospecificity of the hydroxy groups is of minor importance. Most surprising is the enzyme’s inability to recognize JH acid diols. Because JH acid diol cannot be phosphorylated by JHDK, the generally accepted pathway for JH catabolism (JH acid is converted to JH acid diol) must be reconsidered. Still, the role of cellular JHE becomes problematic if the pathway catalyzed by JHEH and JHDK is the major pathway for JH catabolism in the cell. The fact that JH diol phosphate is a significant metabolite certainly weakens the long-held dogma that JH esterase is most important in JH catabolism. While JHE has been noted to have phosphatase activity, to our knowledge it has never been tested on JH diol phosphate.

  • Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994

The sequence and hypothetical structures of M. sexta, D. melanogaster, and B. mori JHDK have been analyzed. A partial characterization of JHDK from whole-body homogenates of D. melanogaster indicates that it is similar to the enzyme in M. sexta, with the exception of its subunit structure. The active D. melanogaster JHDK is a monomer of ~20 kDa, while the active M. sexta (GenBank accession number: AJ430670) and B. mori JHDKs (GenBank accession number: AY363308) are composed of two identical 20 kDa subunits. Similarities in chromatographic properties, isoelectric point, and enzyme activity led  to conclude that sarcoplasmic calcium-binding protein 2 (dSCP2) is the probable D. melanogaster homologue of M. sexta JHDK. The M. sexta gene codes for an enzyme that has 59% sequence identity and >80% similarity to dSCP2 of D. melanogaster (GenBank accession number: AF093240; CG14904).

  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  • Li, S., Zhang, Q.R., Xu, W.H., Schooley, D.A., 2005. The Figure shows a model from this paper of the computer generated structure. Juvenile hormone diol kinase, a calcium-binding protein with kinase activity, from the silkworm, Bombyx mori. Insect Biochem Mol. Biol. 35, 1235-1248
  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881

Li et al reported that the B. mori JHDK is composed of a single exon of 637 bp. The B. mori JHDK is expressed most prevalently in the gut, as determined by Northern blot analyses, and is not under the direct control of JH at the transcriptional level.

  • Li, S., Zhang, Q.R., Xu, W.H., Schooley, D.A., 2005. Juvenile hormone diol kinase, a calcium-binding protein with kinase activity, from the silkworm, Bombyx mori. Insect Biochem Mol. Biol. 35, 1235-1248

Maxwell et al. generated a 3D model that they used for in silico docking simulations. They capitalized on the facts that the catalytic site of JHDK must contain a purine (GTP) binding site and hydrophobic pocket for JH diol, and that the scaffolding for dSCP2 is known. Surrounding the putative substrate-binding site, both the M. sexta and D. melanogaster JHDKs contain the three conserved nucleotide-binding elements common to nucleotide binding proteins. The model further demonstrates that the protein contains four domains that form two pairs of a helix-loop-helix motif (EF-hand;.Charge interactions in the hydrophobic binding pocket, as well as its depth (19 Â), are complementary to the extended conformation of the diol. Moreover, the hydrophobic nature of the binding pocket complements the C1 ester of the substrate and supports the observation that JH diol is the only substrate for this enzyme.

  • Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002b. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  • Branden, C., Tooze, J., 1999. Introduction to Protein Structure, 2nd ed. Garland Publishing, Inc., New York
  • Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890

Usually, an enzyme molecule has only one active site, and the active site fits with one specific type of substrate. An active site contains a binding site that binds the substrate and orients it for catalysis. The orientation of the substrate and the close proximity between it and the active site is so important that in some cases the enzyme can still function properly even though all other parts are mutated and lose function.

Initially, the interaction between the active site and the substrate is non-covalent and transient. There are four important types of interaction that hold the substrate in a defined orientation and form an enzyme-substrate complex (ES complex): hydrogen bonds, van der Waals interactions, hydrophobic interactions and electrostatic force interactions. The charge distribution on the substrate and active site must be complementary, which means all positive and negative charges must be cancelled out. Otherwise, there will be a repulsive force pushing them apart. The active site usually contains non-polar amino acids, although sometimes polar amino acids may also occur. The binding of substrate to the binding site requires at least three contact points in order to achieve stereo-, regio-, and enantioselectivity. For example, alcohol dehydrogenase which catalyses the transfer of a hydride ion from ethanol to NAD+ interacts with the substrate methyl group, hydroxyl group and the pro-(R) hydrogen that will be abstracted during the reaction.

In order to exert their function, enzymes need to assume their correct protein fold (native fold) and tertiary structure. To maintain this defined three-dimensional structure, proteins rely on various types of interactions between their amino acid residues. If these interactions are interfered with, for example by extreme pH values, high temperature or high ion concentrations, this will cause the enzyme to denature and lose its catalytic activity.

A tighter fit between an active site and the substrate molecule is believed to increase the efficiency of a reaction. If the tightness between the active site of DNA polymerase and its substrate is increased, the fidelity, which means the correct rate of DNA replication will also increase. Most enzymes have deeply buried active sites, which can be accessed by a substrate via access channels.

There are three proposed models of how enzymes fit their specific substrate: the lock and key model, the induced fit model, and the conformational selection model. The latter two are not mutually exclusive: conformational selection can be followed by a change in the enzyme’s shape. Additionally, a protein may not wholly follow either model. Amino acids at the binding site of ubiquitin generally follow the induced fit model, whereas the rest of the protein generally adheres to conformational selection. Factors such as temperature likely influences the pathway taken during binding, with higher temperatures predicted to increase the importance of conformational selection and decrease that of induced fit.

  • Lock and key hypothesis
    • This concept was suggested by the 19th-century chemist Emil Fischer. He proposed that the active site and substrate are two stable structures that fit perfectly without any further modification, just like a key fits into a lock. If one substrate perfectly binds to its active site, the interactions between them will be strongest, resulting in high catalytic efficiency.
    • As time went by, limitations of this model started to appear. For example, the competitive enzyme inhibitor methylglucoside can bind tightly to the active site of 4-alpha-glucanotransferase and perfectly fits into it. However, 4-alpha-glucanotransferase is not active on methylglucoside and no glycosyl transfer occurs. The Lock and Key hypothesis cannot explain this, as it would predict a high efficiency of methylglucoside glycosyl transfer due to its tight binding. Apart from competitive inhibition, this theory cannot explain the mechanism of action of non-competitive inhibitors either, as they do not bind to the active site but nevertheless influence catalytic activity.
  • Induced fit hypothesis
  • Conformational selection hypothesis
    • This model suggests that enzymes exist in a variety of conformations, only some of which are capable of binding to a substrate. When a substrate is bound to the protein, the equilibrium in the conformational ensemble shifts towards those able to bind ligands (as enzymes with bound substrates are removed from the equilibrium between the free conformations).
      • Copeland, Robert A. (2013). “Drug–Target Residence Time”. Evaluation of Enzyme Inhibitors in Drug Discovery. John Wiley & Sons, Ltd. pp. 287–344. ISBN 978-1-118-54039-8.

References

  1. Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994
  2. Reversed-phase liquid chromatographic separation of juvenile hormone and its metabolites, and its application for an in vivo juvenile hormone catabolism study in Manduca sexta. Anal. Biochem. 188, 394-397
  3. Grieneisen, M.L., Kieckbusch, T.D., Dorman, G., Latli, B., Prestwich, G.D., Schooley, D.A., 1995
  4. Characterization of the juvenile hormone epoxide hydrolase (JHEH) and juvenile hormone diol phosphotransferase (JHDPT) from Manduca sexta Malpighian tubules. Arch. Insect Biochem. Physiol. 30, 255-270
  5. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  6. Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890
  7. Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994
  8. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  9. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  10. Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890
  11. Grieneisen, M.L., Kieckbusch, T.D., Dorman, G., Latli, B., Prestwich, G.D., Schooley, D.A., 1995
  12. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  13. Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890
  14. Halarnkar, P.P., Jackson, G.P., Straub, K.M., Schooley, D.A., 1993. Juvenile hormone catabolism in Manduca sexta – homologue selectivity of catabolism and identification of a diol-phosphate conjugate as a major end product. Experientia 49, 988-994
  15. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  16. Li, S., Zhang, Q.R., Xu, W.H., Schooley, D.A., 2005. The Figure shows a model from this paper of the computer generated structure. Juvenile hormone diol kinase, a calcium-binding protein with kinase activity, from the silkworm, Bombyx mori. Insect Biochem Mol. Biol. 35, 1235-1248
  17. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  18. Li, S., Zhang, Q.R., Xu, W.H., Schooley, D.A., 2005. Juvenile hormone diol kinase, a calcium-binding protein with kinase activity, from the silkworm, Bombyx mori. Insect Biochem Mol. Biol. 35, 1235-1248
  19. Maxwell, R.A., Welch, W.H., Schooley, D.A., 2002b. JH diol kinase: part I-Purification, characterization and substrate specificity of juvenile hormone selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21874–21881
  20. Branden, C., Tooze, J., 1999. Introduction to Protein Structure, 2nd ed. Garland Publishing, Inc., New York
  21. Maxwell, R.A., Welch, W.H., Horodyski, F.M., Schegg, K.M., Schooley, D.A., 2002. JH diol kinase: part II- Sequencing, cloning, and molecular modeling of juvenile hormone-selective diol kinase from Manduca sexta. J. Biol. Chem. 277, 21882–21890

Category: 

///////////////

Post a Comment

Your email address will not be published. Required fields are marked *