1ARS

X-RAY CRYSTALLOGRAPHIC STUDY OF PYRIDOXAL 5'-PHOSPHATE-TYPE ASPARTATE AMINOTRANSFERASES FROM ESCHERICHIA COLI IN OPEN AND CLOSED FORM

Summary for 1ARS

• Entry DOI: 10.2210/pdb1ars/pdb
• Descriptor: ASPARTATE AMINOTRANSFERASE, PYRIDOXAL-5'-PHOSPHATE (3 entities in total)
• Functional Keywords: transferase(aminotransferase)
• Biological source: Escherichia coli
• Cellular location: Cytoplasm: P00509
• Total number of polymer chains: 1
• Total formula weight: 43866.36

Authors

Okamoto, A.,Higuchi, T.,Hirotsu, K. (deposition date: 1993-08-02, release date: 1994-08-31, Last modification date: 2017-11-29)

Primary citation

Okamoto, A.,Higuchi, T.,Hirotsu, K.,Kuramitsu, S.,Kagamiyama, H.
X-ray crystallographic study of pyridoxal 5'-phosphate-type aspartate aminotransferases from Escherichia coli in open and closed form.
J.Biochem.(Tokyo), 116:95-107, 1994

PubMed Abstract: We determined the three-dimensional structures of aspartate aminotransferase (AspAT) from Escherichia coli and its complex with inhibitor (2-methyl-L-aspartate) at 1.8A resolution. This enzyme reversibly catalyzes the transamination reaction and is a dimer of two identical subunits. Each subunit has 396 amino acid residues and one pyridoxal 5'-phosphate as a cofactor, and is divided into two domains, one large and the other small. Upon binding of the inhibitor, the small domain rotates by 5 degrees toward the large domain to close the active site. This domain movement is caused mainly by small but important main-chain conformational changes in the residues located over the domain interface of the small domain. In chicken mitochondrial AspAT, the domain movement was larger, with a rotational angle of 13 degrees. By comparison of these two structures, the difference in the rotational angles was found to be caused by the larger opening of the domain in the open form of chicken mitochondrial AspAT. Although the overall structures of these two enzymes were almost identical, the surface area of the domain interface in the E. coli enzyme was larger than that in mitochondrial AspAT, suggesting that the structure of the domain interface is responsible for the degree of movement of the small domain.

PubMed: 7798192

Experimental method

X-RAY DIFFRACTION (1.8 Å)