The X-ray crystal structure of l-aspartate ammonia-lyase has been determined to 2.8 A resolution. The enzyme contains three domains, and each domain is composed almost completely of alpha helices. The central domain is composed of five long helices. In the tetramer, these five helices form a 20-helix cluster ...
The X-ray crystal structure of l-aspartate ammonia-lyase has been determined to 2.8 A resolution. The enzyme contains three domains, and each domain is composed almost completely of alpha helices. The central domain is composed of five long helices. In the tetramer, these five helices form a 20-helix cluster. Such clusters have also been seen in delta-crystallin and in fumarase. The active site of aspartase has been located in a region that contains side chains from three different subunits. The structure of the apoenzyme has made it possible to identify some of the residues that are involved in binding the substrate. These residues have been examined by site-directed mutagenesis, and their putative roles have been assigned [Jayasekera, M. M. K., Shi, W., Farber, G. K., & Viola, R. E. (1997) Biochemistry 36, 9145-9150].
Related Citations:
Crystallization and Preliminary X-Ray Studies of L-Aspartase from Escherichia Coli Shi, W., Kidd, R., Giorgianni, F., Schindler, J.F., Viola, R.E., Farber, G.K. (1993) J Mol Biol 234: 1248
Organizational Affiliation:
Department of Biochemistry and Molecular Biology, 108 Althouse Laboratory, The Pennsylvania State University, University Park 16802, USA.
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