Pantothenate kinase from the thermoacidophilic archaeon Picrophilus torridus.
Pantothenate kinase (CoaA) catalyzes the first step of the coenzyme A (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 degrees 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.
Department of Bioresource Science, Ibaraki University College of Agriculture, 3-21-1 Chuo, Ami, Ibaraki 300-0393, Japan.
Masakazu
M
Takagi
Hideyuki
H
Tamaki
Yukiko
Y
Miyamoto
Roberta
R
Leonardi
Satoshi
S
Hanada
Suzanne
S
Jackowski
Shigeru
S
Chohnan
D000105:Acetyl Coenzyme A / Q000378:metabolism; D000595:Amino Acid Sequence; D003065:Coenzyme A / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D020745:Genome, Archaeal / Q000235:genetics; D007700:Kinetics; D008316:Malonyl Coenzyme A / Q000378:metabolism; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D019603:Thermoplasmales / Q000145:classification / Q000201:enzymology*
D008316:Malonyl Coenzyme A; D000105:Acetyl Coenzyme A; D017853:Phosphotransferases (Alcohol Group Acceptor); C023088:pantothenate kinase; D003065:Coenzyme A