JB Accepts, published online ahead of print on 23 October 2009

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J. Bacteriol. doi:10.1128/JB.01021-09
Copyright (c) 2009, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Pantothenate Kinase from Thermoacidophilic Archaeon Picrophilus torridus

Masakazu Takagi, Hideyuki Tamaki, Yukiko Miyamoto, Roberta Leonardi, Satoshi Hanada, Suzanne Jackowski, and Shigeru Chohnan^*

Department of Bioresource Science, Ibaraki University College of Agriculture, 3-21-1 Chuo, Ami, Ibaraki 300-0393, Japan; Institute for Biological Resources and Functions, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8566, Japan; Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105

^* To whom correspondence should be addressed. Email: chohnan{at}mx.ibaraki.ac.jp.

Pantothenate kinase (CoaA) catalyzes the first step of the CoA biosynthetic pathway, and controls the intracellular concentrations of CoA through feedback inhibition in bacteria. An alternative enzyme found in archaea, pantoate kinase, is missing in the order Thermoplasmatales. The PTO0232 gene from Picrophilus torridus, a thermoacidophilic euryarchaeon, is shown to be a distant homologue of the prokaryotic type I CoaA. The cloned gene clearly complements the poor growth of the temperature-sensitive Escherichia coli CoaA mutant strain ts9, and the recombinant protein expressed in E. coli cells transfers phosphate to pantothenate at pH 5 and 55°C. In contrast to E. coli CoaA, the P. torridus enzyme is refractory to feedback regulation by CoA, indicating that in P. torridus cells the CoA levels are not regulated by the CoaA step. These data suggest the existence of two subtypes within the class of prokaryotic type I CoaAs.