1CZC

ASPARTATE AMINOTRANSFERASE MUTANT ATB17/139S/142N WITH GLUTARIC ACID

Summary for 1CZC

• Entry DOI: 10.2210/pdb1czc/pdb
• Related: 1YOO
• Descriptor: PROTEIN (ASPARTATE AMINOTRANSFERASE), PYRIDOXAL-5'-PHOSPHATE, GLUTARIC ACID, ... (4 entities in total)
• Functional Keywords: aspartate aminotransferase, substrate specificity, transferase
• Biological source: Escherichia coli
• Cellular location: Cytoplasm: P00509
• Total number of polymer chains: 1
• Total formula weight: 44041.46

Authors

Okamoto, A.,Oue, S.,Yano, T.,Kagamiyama, H. (deposition date: 1999-09-02, release date: 2000-02-28, Last modification date: 2023-08-09)

Primary citation

Oue, S.,Okamoto, A.,Yano, T.,Kagamiyama, H.
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, 2000

PubMed 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.

PubMed: 10731702

Experimental method

X-RAY DIFFRACTION (2.5 Å)