1eb8

Structure Determinants of Substrate Specificity of Hydroxynitrile Lyase from Manihot esculenta

spinqualitylabelsall models 1eb8, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1eb8 is a 2 chain structure with sequence from Cassava. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MPD Related: 1dwo, 1dwp, 1dwq, 1e89, 1e8d, 1eb9 Activity: Trans-epoxysuccinate hydrolase, with EC number 3.3.2.4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Tryptophan 128 of hydroxynitrile lyase of Manihot esculenta (MeHNL) covers a significant part of a hydrophobic channel that gives access to the active site of the enzyme. This residue was therefore substituted in the mutant MeHNL-W128A by alanine to study its importance for the substrate specificity of the enzyme. Wild-type MeHNL and MeHNL-W128A showed comparable activity on the natural substrate acetone cyanohydrin (53 and 40 U/mg, respectively). However, the specific activities of MeHNL-W128A for the unnatural substrates mandelonitrile and 4-hydroxymandelonitrile are increased 9-fold and approximately 450-fold, respectively, compared with the wild-type MeHNL. The crystal structure of the MeHNL-W128A substrate-free form at 2.1 A resolution indicates that the W128A substitution has significantly enlarged the active-site channel entrance, and thereby explains the observed changes in substrate specificity for bulky substrates. Surprisingly, the MeHNL-W128A--4-hydroxybenzaldehyde complex structure at 2.1 A resolution shows the presence of two hydroxybenzaldehyde molecules in a sandwich type arrangement in the active site with an additional hydrogen bridge to the reacting center. Structure determinants of substrate specificity of hydroxynitrile lyase from Manihot esculenta.,Lauble H, Miehlich B, Forster S, Kobler C, Wajant H, Effenberger F Protein Sci. 2002 Jan;11(1):65-71. PMID:11742123 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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