PDBsum entry 1czc

Transferase

PDB id: 1czc

Contents

Protein chain

396 a.a. *

Ligands

PLP

GUA

Waters ×160

* Residue conservation analysis

PDB id:

1czc

Name:

Transferase

Title:

Aspartate aminotransferase mutant atb17/139s/142n with glutaric acid

Structure:

Protein (aspartate aminotransferase). Chain: a. Synonym: aspat. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 562. Expressed in: escherichia coli. Expression_system_taxid: 562.

Biol. unit:

Dimer (from PDB file)

Resolution:

2.50Å R-factor: 0.182 R-free: 0.243

Authors:

A.Okamoto,S.Oue,T.Yano,H.Kagamiyama

Key ref:

S.Oue et al. (2000). Cocrystallization of a mutant aspartate aminotransferase with a C5-dicarboxylic substrate analog: structural comparison with the enzyme-C4-dicarboxylic analog complex. J Biochem (tokyo), 127, 337-343. PubMed id: 10731702

Date:

02-Sep-99 Release date: 28-Feb-00

Protein chain

P00509  (AAT_ECOLI) -  Aspartate aminotransferase from Escherichia coli (strain K12)

Seq: 396 a.a.

Struc: 396 a.a.*

* PDB and UniProt seqs differ at 15 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.2.6.1.1 - aspartate transaminase.
• Reaction: L-aspartate + 2-oxoglutarate = oxaloacetate + L-glutamate

L-aspartate (Bound ligand (Het Group name = GUA) matches with 90.00% similarity) + 2-oxoglutarate = oxaloacetate + L-glutamate

• Cofactor: Pyridoxal 5'-phosphate

Pyridoxal 5'-phosphate (Bound ligand (Het Group name = PLP) matches with 93.75% similarity)

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

reference

J Biochem (tokyo) 127:337-343 (2000)

PubMed id: 10731702

Cocrystallization of a mutant aspartate aminotransferase with a C5-dicarboxylic substrate analog: structural comparison with the enzyme-C4-dicarboxylic analog complex.

S.Oue, A.Okamoto, T.Yano, H.Kagamiyama.

ABSTRACT

A mutant Escherichia coil aspartate aminotransferase with 17 amino acid substitutions (ATB17), previously created by directed evolution, shows increased activity for beta-branched amino acids and decreased activity for the native substrates, aspartate and glutamate. A new mutant (ATBSN) was generated by changing two of the 17 mutated residues back to the original ones. ATBSN recovered the activities for aspartate and glutamate to the level of the wild-type enzyme while maintaining the enhanced activity of ATB17 for the other amino acid substrates. The absorption spectrum of the bound coenzyme, pyridoxal 5'-phosphate, also returned to the original state. ATBSN shows significantly increased affinity for substrate analogs including succinate and glutarate, analogs of aspartate and glutamate, respectively. Hence, we could cocrystallize ATBSN with succinate or glutarate, and the structures show how the enzyme can bind two kinds of dicarboxylic substrates with different chain lengths. The present results may also provide an insight into the long-standing controversies regarding the mode of binding of glutamate to the wild-type enzyme.