PDBsum entry: 1bjw

Aminotransferase

PDB id: 1bjw

Contents

Protein chains

382 a.a. *

Ligands

PO4 ×2

Waters ×308

* Residue conservation analysis

PDB id:

1bjw

Name:

Aminotransferase

Title:

Aspartate aminotransferase from thermus thermophilus

Structure:

Aspartate aminotransferase. Chain: a, b. Engineered: yes

Source:

Thermus thermophilus. Organism_taxid: 300852. Strain: hb8. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

1.80Å R-factor: 0.215 R-free: 0.269

Authors:

T.Nakai,K.Okada,S.Kuramitsu,K.Hirotsu,Riken Structural Genomics/proteomics Initiative (Rsgi)

Key ref:

T.Nakai et al. (1999). Structure of Thermus thermophilus HB8 aspartate aminotransferase and its complex with maleate. Biochemistry, 38, 2413-2424. PubMed id: 10029535 DOI: 10.1021/bi9819881

Date:

30-Jun-98 Release date: 22-Jul-99

Protein chains

Q56232  (AAT_THET8) -  Aspartate aminotransferase

Seq: 385 a.a.

Struc: 382 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.2.6.1.1 - Aspartate transaminase.
• Reaction: L-aspartate + 2-oxoglutarate = oxaloacetate + L-glutamate
• Cofactor: Pyridoxal 5'-phosphate

Molecule diagrams generated from .mol files obtained from the KEGG ftp site

 Gene Ontology (GO) functional annotation 

• Cellular component: cytoplasm (1 term)
• Biological process: biosynthetic process (2 terms)
• Biochemical function: catalytic activity (8 terms)

reference

DOI no: 10.1021/bi9819881

Biochemistry 38:2413-2424 (1999)

PubMed id: 10029535

Structure of Thermus thermophilus HB8 aspartate aminotransferase and its complex with maleate.

T.Nakai, K.Okada, S.Akutsu, I.Miyahara, S.Kawaguchi, R.Kato, S.Kuramitsu, K.Hirotsu.

ABSTRACT

The three-dimensional structures of pyridoxal 5'-phosphate-type aspartate aminotransferase (AspAT) from Thermus thermophilus HB8 and pyridoxamine 5'-phosphate type one in complex with maleate have been determined by X-ray crystallography at 1.8 and 2.6 A resolution, respectively. The enzyme is a homodimer, and the polypeptide chain of the subunit is folded into one arm, one small domain, and one large domain. AspATs from many species were classified into aminotransferase subgroups Ia and Ib. The enzyme belongs to subgroup Ib, its sequence being less than 16% identical to the primary sequences of Escherichia coli, pig cytosolic, and chicken mitochondrial AspATs, which belong to subgroup Ia whose sequences are more than 40% identical and whose three-dimensional structures are quite similar with the active site residues almost completely conserved. The first X-ray analysis of AspAT subgroup Ib indicated that the overall and the active site structures are essentially conserved between the AspATs of subgroup Ia and the enzyme of subgroup Ib, but there are two distinct differences between them. (1) In AspAT subgroup Ia, substrate (or inhibitor) binding induces a large movement of the small domain as a whole to close the active site. However, in the enzyme of subgroup Ib, only the N-terminal region (Lys13-Val30) of the small domain approaches the active site to interact with the maleate. (2) In AspAT subgroup Ia, Arg292 recognizes the side chain carboxylate of the substrate; however, residue 292 of the enzyme in subgroup Ib is not Arg, and in place of Arg292, Lys109 forms a salt bridge with the side chain carboxylate. The thermostability of the enzyme is attained at least in part by the high content of Pro residues in the beta-turns and the marked increase in the number of salt bridges on the molecular surface compared with the mesophilic AspAT.