1ars
X-RAY CRYSTALLOGRAPHIC STUDY OF PYRIDOXAL 5'-PHOSPHATE-TYPE ASPARTATE AMINOTRANSFERASES FROM ESCHERICHIA COLI IN OPEN AND CLOSED FORM
|
OverviewOverview
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.
About this StructureAbout this Structure
1ARS is a Single protein structure of sequence from Escherichia coli with PLP as ligand. Active as Aspartate transaminase, with EC number 2.6.1.1 Full crystallographic information is available from OCA.
ReferenceReference
X-ray crystallographic study of pyridoxal 5'-phosphate-type aspartate aminotransferases from Escherichia coli in open and closed form., Okamoto A, Higuchi T, Hirotsu K, Kuramitsu S, Kagamiyama H, J Biochem (Tokyo). 1994 Jul;116(1):95-107. PMID:7798192
Page seeded by OCA on Tue Nov 20 11:04:58 2007