1g94

CRYSTAL STRUCTURE ANALYSIS OF THE TERNARY COMPLEX BETWEEN PSYCHROPHILIC ALPHA AMYLASE FROM PSEUDOALTEROMONAS HALOPLANCTIS IN COMPLEX WITH A HEPTA-SACCHARIDE AND A TRIS MOLECULE

spinqualitylabelsall models 1g94, resolution 1.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1g94 is a 1 chain structure with sequence from Pseudoalteromonas haloplanktis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.74Å Ligands: CA, CL, DAF, GLC, TRS Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function AMY_PSEHA 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 The psychrophilic Pseudoalteromonas haloplanctis alpha-amylase is shown to form ternary complexes with two alpha-amylase inhibitors present in the active site region, namely, a molecule of Tris and a trisaccharide inhibitor or heptasaccharide inhibitor, respectively. The crystal structures of these complexes have been determined by X-ray crystallography to 1.80 and 1.74 A resolution, respectively. In both cases, the prebound inhibitor Tris is expelled from the active site by the incoming oligosaccharide inhibitor substrate analogue, but stays linked to it, forming well-defined ternary complexes with the enzyme. These results illustrate competition in the crystalline state between two inhibitors, an oligosaccharide substrate analogue and a Tris molecule, bound at the same time in the active site region. Taken together, these structures show that the enzyme performs transglycosylation in the complex with the pseudotetrasaccharide acarbose (confirmed by a mutant structure), leading to a well-defined heptasaccharide, considered as a more potent inhibitor. Furthermore, the substrate-induced ordering of water molecules within a channel highlights a possible pathway used for hydrolysis of starch and related poly- and oligosaccharides. Crystallographic evidence of a transglycosylation reaction: ternary complexes of a psychrophilic alpha-amylase.,Aghajari N, Roth M, Haser R Biochemistry. 2002 Apr 2;41(13):4273-80. PMID:11914073 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Amylase 3D structures

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