Publication
Title
Crystal structure of **Sulfolobus acidocaldarius** aspartate carbamoyltransferase in complex with its allosteric activator CTP
Author
Abstract
Aspartate carbamoyltransferase (ATCase) is a paradigm for allosteric regulation of enzyme activity. B-class ATCases display very similar homotropic allosteric behaviour, but differ extensively in their heterotropic patterns. The ATCase from the thermoacidophilic archaeon Sulfolobus acidocaldarius, for example, is strongly activated by its metabolic pathway′s end product CTP, in contrast with Escherichia coli ATCase which is inhibited by CTP. To investigate the structural basis of this property, we have solved the crystal structure of the S. acidocaldarius enzyme in complex with CTP. Structure comparison reveals that effector binding does not induce similar large-scale conformational changes as observed for the E. coli ATCase. However, shifts in sedimentation coefficients upon binding of the bi-substrate analogue PALA show the existence of structurally distinct allosteric states. This suggests that the so-called Nucleotide-Perturbation model for explaining heterotropic allosteric behaviour, which is based on global conformational strain, is not a general mechanism of B-class ATCases.
Language
English
Source (journal)
Biochemical and biophysical research communications. - New York, N.Y.
Publication
New York, N.Y. : 2008
ISSN
0006-291X
Volume/pages
372:1(2008), p. 40-44
ISI
000256874400007
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Faculty/Department
Publication type
Subject
External links
Web of Science
Record
Identification
Creation 01.04.2015
Last edited 12.12.2017