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462 a.a.
Key reference
DOI no: 10.1016/j.ibmb.2005.07.004 Insect Biochem Mol Biol 35:1311-1320 (2005) PubMed id: 16291087
Crystal structure at 1.1 Angstroms resolution of an insect myrosinase from Brevicoryne brassicae shows its close relationship to beta-glucosidases. H.Husebye, S.Arzt, W.P.Burmeister, F.V.Härtel, A.Brandt, J.T.Rossiter, A.M.Bones. ABSTRACT
The aphid Brevicoryne brassicae is a specialist feeding on Brassicaceae plants. The insect has an intricate defence system involving a beta-D-thioglucosidase (myrosinase) that hydrolyses glucosinolates sequestered from the host plant into volatile isothiocyanates. These isothiocyanates act synergistically with the pheromone E-beta-farnesene to form an alarm system when the aphid is predated. In order to investigate the enzymatic characteristics of the aphid myrosinase and its three-dimensional structure, milligram amounts of pure recombinant aphid myrosinase were obtained from Echerichia coli. The recombinant enzyme had similar physiochemical properties to the native enzyme. The global structure is very similar to Sinapis alba myrosinase and plant beta-O-glucosidases. Aphid myrosinase has two catalytic glutamic acid residues positioned as in plant beta-O-glucosidases, and it is not obvious why this unusual enzyme hydrolyses glucosinolates, the common substrates of plant myrosinases which are normally not hydrolyzed by plant beta-O-glucosidases. The only residue specific for aphid myrosinase in proximity of the glycosidic linkage is Tyr180 which may have a catalytic role. The aglycon binding site differs strongly from plant myrosinase, whereas due to the presence of Trp424 in the glucose binding site, this part of the active site is more similar to plant beta-O-glucosidases, as plant myrosinases carry a phenylalanine residue at this position.
Literature references that cite this PDB file's key reference
PubMed id Reference
19224919 R.Kissen, and A.M.Bones (2009).
Nitrile-specifier Proteins Involved in Glucosinolate Hydrolysis in Arabidopsis thaliana.J Biol Chem, 284, 12057-12070.
19701726 R.Kissen, T.W.Pope, M.Grant, J.A.Pickett, J.T.Rossiter, and G.Powell (2009).
Modifying the alkylglucosinolate profile in Arabidopsis thaliana alters the tritrophic interaction with the herbivore Brevicoryne brassicae and parasitoid Diaeretiella rapae.J Chem Ecol, 35, 958-969.
18422657 L.M.Mendonça, and S.R.Marana (2008).
The role in the substrate specificity and catalysis of residues forming the substrate aglycone-binding site of a beta-glycosidase.FEBS J, 275, 2536-2547.
17623639 E.Kazana, T.W.Pope, L.Tibbles, M.Bridges, J.A.Pickett, A.M.Bones, G.Powell, and J.T.Rossiter (2007).
The cabbage aphid: a walking mustard oil bomb.Proc Biol Sci, 274, 2271-2277.
17333371 J.D.Blande, J.A.Pickett, and G.M.Poppy (2007).
A Comparison of Semiochemically Mediated Interactions Involving Specialist and Generalist Brassica-feeding Aphids and the Braconid Parasitoid Diaeretiella rapae.J Chem Ecol, 33, 767-779.
17619221 K.L.Falk, and J.Gershenzon (2007).
The desert locust, Schistocerca gregaria, detoxifies the glucosinolates of Schouwia purpurea by desulfation.J Chem Ecol, 33, 1542-1555. The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.
