A thermostable K(+)-stimulated vacuolar-type pyrophosphatase from the hyperthermophilic bacterium Thermotoga maritima.
Current evidence suggests the occurrence of two classes of vacuolar-type H(+)-translocating inorganic pyrophosphatases (V-PPases): K(+)-insensitive proteins, identified in eukaryotes, bacteria and archaea, and K(+)-stimulated V-PPases, identified to date only in eukaryotes. Here, we describe the functional characterization of a thermostable V-PPase from the anaerobic hyperthermophilic bacterium Thermotoga maritima by heterologous expression in Saccharomyces cerevisiae. The activity of this 71-kDa membrane-embedded polypeptide has a near obligate requirement for K(+), like the plant V-PPase, and its thermostability depends on the binding of Mg(2+). Phylogenetic analysis of protein sequences consistently assigned the T. maritima V-PPase to the K(+)-sensitive class of V-PPases so far only known for eukaryotes. The finding of a K(+)-stimulated V-PPase also in a member of a primitive eubacterial lineage strongly supports an ancient evolutionary origin of this group of pyrophosphate-energized proton pumps.
Pérez-Castiñeira
J R
JR
Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Americo Vespucio s/n, 41092 Sevilla, Spain.
López-Marqués
R L
RL
Losada
M
M
Serrano
A
A
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011756:Diphosphates / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability / Q000187:drug effects / Q000502:physiology; D015151:Immunoblotting; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D008970:Molecular Weight; D010802:Phylogeny; D011188:Potassium / Q000378:metabolism* / Q000494:pharmacology; D011755:Pyrophosphatases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics; D013696:Temperature; D020124:Thermotoga maritima; D014617:Vacuoles / Q000201:enzymology*
D001426:Bacterial Proteins; D011756:Diphosphates; D011755:Pyrophosphatases; C426763:TVP protein, Thermotoga maritima; D008274:Magnesium; D011188:Potassium