1aqm

ALPHA-AMYLASE FROM ALTEROMONAS HALOPLANCTIS COMPLEXED WITH TRIS

spinqualitylabelsall models 1aqm, resolution 1.85Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1aqm 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 1.85Å Ligands: CA, CL, 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 Alteromonas haloplanctis is a bacterium that flourishes in Antarctic sea-water and it is considered as an extreme psychrophile. We have determined the crystal structures of the alpha-amylase (AHA) secreted by this bacterium, in its native state to 2.0 angstroms resolution as well as in complex with Tris to 1.85 angstroms resolution. The structure of AHA, which is the first experimentally determined three-dimensional structure of a psychrophilic enzyme, resembles those of other known alpha-amylases of various origins with a surprisingly greatest similarity to mammalian alpha-amylases. AHA contains a chloride ion which activates the hydrolytic cleavage of substrate alpha-1,4-glycosidic bonds. The chloride binding site is situated approximately 5 angstroms from the active site which is characterized by a triad of acid residues (Asp 174, Glu 200, Asp 264). These are all involved in firm binding of the Tris moiety. A reaction mechanism for substrate hydrolysis is proposed on the basis of the Tris inhibitor binding and the chloride activation. A trio of residues (Ser 303, His 337, Glu 19) having a striking spatial resemblance with serine-protease like catalytic triads was found approximately 22 angstroms from the active site. We found that this triad is equally present in other chloride dependent alpha-amylases, and suggest that it could be responsible for autoproteolytic events observed in solution for this cold adapted alpha-amylase. Crystal structures of the psychrophilic alpha-amylase from Alteromonas haloplanctis in its native form and complexed with an inhibitor.,Aghajari N, Feller G, Gerday C, Haser R Protein Sci. 1998 Mar;7(3):564-72. PMID:9541387 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Amylase 3D structures

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