Gas Channels for NH3: Proteins from Hyperthermophiles Complement an Escherichia coli Mutant

ABSTRACT Ammonium transport (Amt) proteins appear to be bidirectional channels for NH3. The amt genes of the hyperthermophiles Aquifex aeolicus and Methanococcus jannaschii complement enteric amtB mutants for growth at 25 nM NH3 at 37°C. To our knowledge, Amt proteins are the first hyperthermophilic membrane transport proteins shown to be active in a mesophilic bacterium. Despite low expression levels, His-tagged Aquifex Amt could be purified by heating and nickel chelate affinity chromatography. It could be studied genetically in Escherichia coli.

[1]  S. Kustu,et al.  Ammonium/methylammonium transport (Amt) proteins facilitate diffusion of NH3 bidirectionally , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[2]  D. Hunt,et al.  Cytosolic malate dehydrogenase confers selectivity of the nucleic acid-conducting channel , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[3]  S. Kustu,et al.  Evidence that Fungal MEP Proteins Mediate Diffusion of the Uncharged Species NH3 across the Cytoplasmic Membrane , 2001, Molecular and Cellular Biology.

[4]  C. Huang,et al.  New insights into the Rh superfamily of genes and proteins in erythroid cells and nonerythroid tissues. , 2001, Blood cells, molecules & diseases.

[5]  Stefan Schouten,et al.  Widespread occurrence of structurally diverse tetraether membrane lipids: evidence for the ubiquitous presence of low-temperature relatives of hyperthermophiles. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[6]  B. André,et al.  In vivo N‐glycosylation of the Mep2 high‐affinity ammonium transporter of Saccharomyces cerevisiae reveals an extracytosolic N‐terminus , 2000, Molecular microbiology.

[7]  G. Thomas,et al.  Membrane topology of the Mep/Amt family of ammonium transporters , 2000, Molecular microbiology.

[8]  S. Howitt,et al.  Structure, function and regulation of ammonium transporters in plants. , 2000, Biochimica et biophysica acta.

[9]  C. Huang,et al.  Molecular biology and genetics of the Rh blood group system. , 2000, Seminars in hematology.

[10]  W. Frommer,et al.  The molecular physiology of ammonium uptake and retrieval. , 2000, Current opinion in plant biology.

[11]  D Kozono,et al.  Functional reconstitution and characterization of AqpZ, the E. coli water channel protein. , 1999, Journal of molecular biology.

[12]  S. Kustu,et al.  Ammonia acquisition in enteric bacteria: physiological role of the ammonium/methylammonium transport B (AmtB) protein. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[13]  T. Leisinger,et al.  Involvement of CysB and Cbl regulatory proteins in expression of the tauABCD operon and other sulfate starvation-inducible genes in Escherichia coli , 1997, Journal of bacteriology.

[14]  R. Iwanicka-Nowicka,et al.  A new gene, cbl, encoding a member of the LysR family of transcriptional regulators belongs to Escherichia coli cys regulon. , 1995, Gene.

[15]  S. Kustu,et al.  Purification of the alternative sigma factor, sigma 54, from Salmonella typhimurium and characterization of sigma 54-holoenzyme. , 1991, The Journal of biological chemistry.