1G9H
TERNARY COMPLEX BETWEEN PSYCHROPHILIC ALPHA-AMYLASE, COMII (PSEUDO TRI-SACCHARIDE FROM BAYER) AND TRIS (2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL)
Summary for 1G9H
| Entry DOI | 10.2210/pdb1g9h/pdb |
| Related | 1AQH 1AQM 1B0I 1G94 |
| Descriptor | ALPHA-AMYLASE, 4,6-dideoxy-4-{[(1S,5R,6S)-3-formyl-5,6-dihydroxy-4-oxocyclohex-2-en-1-yl]amino}-alpha-D-xylo-hex-5-enopyranose-(1-4)-beta-D-glucopyranose, CALCIUM ION, ... (6 entities in total) |
| Functional Keywords | alpha-beta 8 barrel, 3 domain structure, hydrolase |
| Biological source | Pseudoalteromonas haloplanktis |
| Cellular location | Secreted : P29957 |
| Total number of polymer chains | 1 |
| Total formula weight | 49622.52 |
| Authors | Aghajari, N.,Roth, M.,Haser, R. (deposition date: 2000-11-23, release date: 2002-06-26, Last modification date: 2023-08-09) |
| Primary citation | AGHAJARI, N.,ROTH, M.,HASER, R. Crystallographic evidence of a transglycosylation reaction: ternary complexes of a psychrophilic alpha-amylase. Biochemistry, 41:4273-4280, 2002 Cited by PubMed Abstract: 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. PubMed: 11914073DOI: 10.1021/bi0160516 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.8 Å) |
Structure validation
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