2at2

From Proteopedia

Revision as of 06:14, 21 November 2007

MOLECULAR STRUCTURE OF BACILLUS SUBTILIS ASPARTATE TRANSCARBAMOYLASE AT 3.0 ANGSTROMS RESOLUTION

Overview

The three-dimensional structure of Bacillus subtilis aspartate, transcarbamoylase (ATCase; aspartate carbamoyltransferase;, carbamoyl-phosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2) has been, solved by the molecular replacement method at 3.0 A resolution and refined, to a crystallographic R factor of 0.19. The enzyme crystallizes in the, space group C2 with unit cell dimensions a = 258.5, b = 153.2, and c =, 51.9 A and beta = 97.7 degrees. The asymmetric unit is composed of three, monomers related by noncrystallographic threefold symmetry. A total of 295, of 304 amino acid residues have been built into the monomer. The last 9, residues in the C terminus were not included in the final model. Each, monomer consists of 34% alpha-helix and 18% beta-strand. Three, solvent-exposed loop regions (residues 69-84, 178-191, and 212-229) are, not well defined in terms of electron density. The catalytic trimer of, ATCase from B. subtilis shows great similarity to the catalytic trimer in, Escherichia coli ATCase, which was used in constructing the model for, molecular replacement. The unliganded trimer from B. subtilis, which is, not cooperative, resembles the T (inactive) state slightly more than the R, (active)-state form of the E. coli trimer. However, certain regions in the, B. subtilis trimer exhibit shifts toward the E. coli R-state conformation.

About this Structure

2AT2 is a Single protein structure of sequence from Bacillus subtilis. Active as Aspartate carbamoyltransferase, with EC number 2.1.3.2 Full crystallographic information is available from OCA.

Reference

Molecular structure of Bacillus subtilis aspartate transcarbamoylase at 3.0 A resolution., Stevens RC, Reinisch KM, Lipscomb WN, Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):6087-91. PMID:1906175

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