type	Journal Article
authors	Jeffery, C. J.; Barry, T.; Doonan, S.; Petsko, G. A.; Ringe, D.
title	Crystal structure of Saccharomyces cerevisiae cytosolic aspartate aminotransferase
journal	Protein Sci
Activity	2.6.1.1
Family	2.6.1.1.a
sel	selected
ui	9655342
year	(1998)
volume	7
number	6
pages	1380-7
keywords	Animal
abstract	The crystal structure of Saccharomyces cerevisiae cytoplasmic aspartate aminotransferase (EC 2.6.1.1) has been determined to 2.05 A resolution in the presence of the cofactor pyridoxal-5'-phosphate and the competitive inhibitor maleate. The structure was solved by the method of molecular replacement. The final value of the crystallographic R- factor after refinement was 23.1% with good geometry of the final model. The yeast cytoplasmic enzyme is a homodimer with two identical active sites containing residues from each subunit. It is found in the "closed" conformation with a bound maleate inhibitor in each active site. It shares the same three-dimensional fold and active site residues as the aspartate aminotransferases from Escherichia coli, chicken cytoplasm, and chicken mitochondria, although it shares less than 50% sequence identity with any of them. The availability of four similar enzyme structures from distant regions of the evolutionary tree provides a measure of tolerated changes that can arise during millions of years of evolution.
last changed	2010/11/09 16:02