Nucleotide-protectable labeling of sulfhydryl groups in subunit I of the ATPase from Halobacterium saccharovorum.
A membrane-bound ATPase from the archaebacterium Halobacterium saccharovorum is inhibited by N-ethylmaleimide in a nucleotide-protectable manner (Stan-Lotter et al., 1991, Arch. Biochem. Biophys. 284, 116-119). When the enzyme was incubated with N-[14C]ethylmaleimide, the bulk of radioactivity was associated with the 87,000-Da subunit (subunit I). ATP, ADP, or AMP reduced incorporation of the inhibitor. No charge shift of subunit I was detected following labeling with N-ethylmaleimide, indicating an electroneutral reaction. The results are consistent with the selective modification of sulfhydryl groups in subunit I at or near the catalytic site and are further evidence of a resemblance between this archaebacterial ATPase and the vacuolar-type ATPases.
Sulzner
M
M
Institut für Mikrobiologie und Genetik, Universität Wien, Vienna, Austria.
Stan-Lotter
H
H
Hochstein
L I
LI
D000227:Adenine Nucleotides / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000302:isolation & purification / Q000378:metabolism*; D002462:Cell Membrane / Q000201:enzymology; D005033:Ethylmaleimide / Q000378:metabolism*; D006217:Halobacterium / Q000201:enzymology*; D007700:Kinetics; D046911:Macromolecular Substances; D008970:Molecular Weight; D011485:Protein Binding; D013438:Sulfhydryl Compounds / Q000378:metabolism
D000227:Adenine Nucleotides; D046911:Macromolecular Substances; D013438:Sulfhydryl Compounds; D000251:Adenosine Triphosphatases; D005033:Ethylmaleimide