3daa
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| , resolution 1.9Å | |||||||
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| Sites: | and | ||||||
| Ligands: | |||||||
| Activity: | D-amino-acid transaminase, with EC number 2.6.1.21 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
CRYSTALLOGRAPHIC STRUCTURE OF D-AMINO ACID AMINOTRANSFERASE INACTIVATED BY PYRIDOXYL-D-ALANINE
OverviewOverview
The three-dimensional structures of two forms of the D-amino acid aminotransferase (D-aAT) from Bacillus sp. YM-1 have been determined crystallographically: the pyridoxal phosphate (PLP) form and a complex with the reduced analogue of the external aldimine, N-(5'-phosphopyridoxyl)-d-alanine (PPDA). Together with the previously reported pyridoxamine phosphate form of the enzyme [Sugio et al. (1995) Biochemistry 34, 9661], these structures allow us to describe the pathway of the enzymatic reaction in structural terms. A major determinant of the enzyme's stereospecificity for D-amino acids is a group of three residues (Tyr30, Arg98, and His100, with the latter two contributed by the neighboring subunit) forming four hydrogen bonds to the substrate alpha-carboxyl group. The replacement by hydrophobic groups of the homologous residues of the branched chain L-amino acid aminotransferase (which has a similar fold) could explain its opposite stereospecificity. As in L-aspartate aminotransferase (L-AspAT), the cofactor in D-aAT tilts (around its phosphate group and N1 as pivots) away from the catalytic lysine 145 and the protein face in the course of the reaction. Unlike L-AspAT, D-aAT shows no other significant conformational changes during the reaction.
About this StructureAbout this Structure
3DAA is a Single protein structure of sequence from Bacillus sp.. Full crystallographic information is available from OCA.
ReferenceReference
Crystallographic study of steps along the reaction pathway of D-amino acid aminotransferase., Peisach D, Chipman DM, Van Ophem PW, Manning JM, Ringe D, Biochemistry. 1998 Apr 7;37(14):4958-67. PMID:9538014
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