Acidophilic adaptations in the structure of Acetobacter aceti N5-carboxyaminoimidazole ribonucleotide mutase (PurE).Settembre, E.C., Chittuluru, J.R., Mill, C.P., Kappock, T.J., Ealick, S.E.
(2004) Acta Crystallogr D Biol Crystallogr 60: 1753-1760
- PubMed: 15388921
- DOI: https://doi.org/10.1107/S090744490401858X
- Primary Citation of Related Structures:
- PubMed Abstract:
The crystal structure of Acetobacter aceti PurE was determined to a resolution of 1.55 A and is compared with the known structures of the class I PurEs from a mesophile, Escherichia coli, and a thermophile, Thermotoga maritima. Analyses of the general factors that increase protein stability are examined as potential explanations for the acid stability of A. aceti PurE. Increased inter-subunit hydrogen bonding and an increased number of arginine-containing salt bridges appear to account for the bulk of the increased acid stability. A chain of histidines linking two active sites is discussed in the context of the proton transfers catalyzed by the enzyme.
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853, USA.