Publications

• Sequence of subunit c of the Na(+)-translocating F1F0 ATPase of Acetobacterium woodii: proposal for determinants of Na+ specificity as revealed by sequence comparisons.

  Rahlfs S., Muller V.

  A 3.2 kb EcoRI fragment carrying genes for Na(+)-F1F0 ATPase was cloned from chromosomal DNA of Acetobacterium woodii. DNA sequence analysis revealed the presence of an open reading frame which was identified by data base searches and comparison with the experimentally derived N-terminal amino aci ... >> More

  A 3.2 kb EcoRI fragment carrying genes for Na(+)-F1F0 ATPase was cloned from chromosomal DNA of Acetobacterium woodii. DNA sequence analysis revealed the presence of an open reading frame which was identified by data base searches and comparison with the experimentally derived N-terminal amino acid sequence to code for subunit c of Na(+)-F1F0 ATPase. A comparison of the primary sequences of the two well established Na(+)-translocating F1F0 ATPases from Acetobacterium woodii and Propionigenium modestum with H(+)-translocating enzymes indicates the length of the C-terminus as well as specific residues located in the cytoplasmic membrane to be important for Na+ transport. << Less

  FEBS Lett 404:269-271(1997) [PubMed] [EuropePMC]

• Operon of vacuolar-type Na(+)-ATPase of Enterococcus hirae.

  Solioz M., Davies K.

  The Gram-positive bacteria Enterococcus hirae expel sodium by two systems: a Na+/H(+)-antiporter and a vacuolar-type Na(+)-ATPase. We isolated a mutant, NalkA, defective in the Na(+)-ATPase. NalkA grew normally at neutral pH but was unable to grow in the presence of > 100 mM sodium at pH 9.5. By f ... >> More

  The Gram-positive bacteria Enterococcus hirae expel sodium by two systems: a Na+/H(+)-antiporter and a vacuolar-type Na(+)-ATPase. We isolated a mutant, NalkA, defective in the Na(+)-ATPase. NalkA grew normally at neutral pH but was unable to grow in the presence of > 100 mM sodium at pH 9.5. By functional complementation at high pH, we cloned pES1, a plasmid from an E. hirae gene bank containing a 5.2-kilobase pair region of genomic DNA. The genomic DNA in pES1 contains five complete open reading frames, ntpM, -N, -O, -P, and -Q, encoding proteins of 75, 16, 23, 38, and 11 kDa. A sixth incomplete open reading frame, ntp 'L, precedes ntpM. The 3'-end of the cloned DNA overlaps with a previously published sequence encoding the ntpA and ntpB subunits of the E. hirae Na(+)-ATPase (Takase, K., Yamato, I., and Kakinuma, Y. 1993) J. Biol. Chem. 268, 11610-11616). The insert of pES1 therefore represents the upstream region of the ntp operon that encodes the E. hirae Na(+)-ATPase. Complementation analysis with various deletions derived from pES1 suggest that the original mutation is in the ntpM gene. Of the new genes described here, three exhibited significant sequence similarity to known proteins; ntpM shares 24% identical amino acid residues with the "116-kDa" subunits of eukaryotic vacuolar ATPases, ntpN exhibits 28% sequence identity with the 16-kDa proteolipid of human vacuolar ATPase, and ntpO has sequence homology to the 31-kDa subunit of the bovine kidney vacuolar ATPase. No known proteins with sequence similarity to ntp'L, -P, or -Q could be identified. Disruption of either ntpM, -N, or -O in wild-type cells by cassette mutagenesis resulted in mutants unable to effect ATP-driven sodium extrusion. NtpM, -N, and -O therefore represent three new gene products involved in sodium extrusion by the vacuolar-type Na(+)-ATPase of E. hirae, and three more gene products, NtpL, -P, and -Q, may also be constituents of this enzyme. The ntp operon thus contains at least eight genes. << Less

  J. Biol. Chem. 269:9453-9459(1994) [PubMed] [EuropePMC]

• Sequencing and characterization of the ntp gene cluster for vacuolar-type Na(+)-translocating ATPase of Enterococcus hirae.

  Takase K., Kakinuma S., Yamato I., Konishi K., Igarashi K., Kakinuma Y.

  We have previously reported the DNA and amino acid sequences for the three genes (ntpA, ntpB, and ntpK) encoding the A, B, and K (proteolipid) subunits, respectively, of Na(+)-translocating ATPase of a eubacterium Enterococcus hirae (Kakinuma, Y., Kakinuma, S., Takase, K., Konishi, K., Igarashi, K ... >> More

  We have previously reported the DNA and amino acid sequences for the three genes (ntpA, ntpB, and ntpK) encoding the A, B, and K (proteolipid) subunits, respectively, of Na(+)-translocating ATPase of a eubacterium Enterococcus hirae (Kakinuma, Y., Kakinuma, S., Takase, K., Konishi, K., Igarashi, K., and Yamato, I. (1993) Biochem. Biophys. Res. Commun. 195, 1063-1069). In this paper we report the entire nucleotide sequence of the ntp gene cluster coding for this multisubunit enzyme. The cluster contained eight other genes; the order of these 11 genes was ntpF, -I, -K, -E, -C, -G, -A, -B, -D, -H, and -J, encoding proteins with predicted molecular weights of 14,255, 75,619, 16,036, 22,699, 38,162, 11,409, 65,766, 51,139, 27,093, 7,164, and 48,869, respectively. The deduced amino acid sequences of these products suggested that NtpI and NtpJ are hydrophobic proteins and others are hydrophilic. The ntpI gene product, which possesses six membrane-spanning segments in its carboxyl-terminal half, resembled the 116-kDa subunit of vacuolar (V)-ATPase in clathrin-coated vesicles. In addition, the NtpE, NtpC, NtpG, and NtpD proteins resembled bovine kidney ATPase E subunit, Saccharomyces cerevisiae Vma6p, Manduca sexta V-ATPase 14-kDa subunit, and Sulfolobus acidocaldarius gamma subunit, respectively, although the similarities between their amino acid sequences were moderate. Other gene products (NtpF and NtpH) did not show significant sequence similarity to other V-ATPase subunits. Since NtpA, NtpB, and NtpK are homologous counterparts of V-ATPase, these findings suggest that the molecular architecture of E. hirae Na(+)-ATPase complex corresponds to the V-type H(+)-ATPase complex distributed in various eukaryotic endomembrane systems. The sequence of the NtpJ product was similar to those of K+ transport systems of S. cerevisiae (Trk1 and Trk2); its meaning will be discussed. This is the first demonstration of a eukaryotic V-ATPase-like Na+ pump in bacteria. << Less

  J. Biol. Chem. 269:11037-11044(1994) [PubMed] [EuropePMC]