Table of Contents Author Guidelines Submit a Manuscript
Archaea
Volume 2014 (2014), Article ID 176863, 9 pages
http://dx.doi.org/10.1155/2014/176863
Research Article

Characterization of Ten Heterotetrameric NDP-Dependent Acyl-CoA Synthetases of the Hyperthermophilic Archaeon Pyrococcus furiosus

Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA

Received 11 October 2013; Accepted 9 December 2013; Published 11 February 2014

Academic Editor: Yoshizumi Ishino

Copyright © 2014 Joseph W. Scott et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The hyperthermophilic archaeon Pyrococcus furiosus grows by fermenting peptides and carbohydrates to organic acids. In the terminal step, acyl-CoA synthetase (ACS) isoenzymes convert acyl-CoA derivatives to the corresponding acid and conserve energy in the form of ATP. ACS1 and ACS2 were previously purified from P. furiosus and have structures but the genome contains genes encoding three additional -subunits. The ten possible combinations of and genes were expressed in E. coli and each resulted in stable and active isoenzymes. The -subunit of each isoenzyme determined CoA-based substrate specificity and between them they accounted for the CoA derivatives of fourteen amino acids. The -subunit determined preference for adenine or guanine nucleotides. The GTP-generating isoenzymes are proposed to play a role in gluconeogenesis by producing GTP for GTP-dependent phosphoenolpyruvate carboxykinase and for other GTP-dependent processes. Transcriptional and proteomic data showed that all ten isoenzymes are constitutively expressed indicating that both ATP and GTP are generated from the metabolism of most of the amino acids. A phylogenetic analysis showed that the ACSs of P. furiosus and other members of the Thermococcales are evolutionarily distinct from those found throughout the rest of biology, including those of other hyperthermophilic archaea.