title: Proton-pumping inorganic pyrophosphatases in some archaea and other extremophilic prokaryotes.
abstract: Comparative studies between the proton-pumping, membrane-bound inorganic pyrophosphatases (H(+)-PPases) from hyperthermophilic and thermophilic prokaryotes and those from mesophilic organisms can now be performed because of very recent sequence data. Typical overall factors that contribute to protein thermostability are found in H(+)-PPases from extremophiles; nevertheless, putative active site motifs of this class of enzymes may be identical over the whole range of average growth temperatures of the compared prokaryotes. Heterologous expression in yeast of H(+)-PPases from organisms spanning a wide range of thermal habitats has allowed the biochemical comparison among these proteins within the same system, ensuring that differences observed are due to intrinsic characteristics of the proteins and not to their interactions with different cellular environments. On the other hand, the availability of H(+)-PPase sequences from a variety of sources have permitted molecular phylogenetic studies of this class of proton pumps, thus providing information about their general structural and functional properties. A great step forward may be expected when one of the several groups now attempting crystallization and 3D structural determination of H(+)-PPases will be successful.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, CSIC-Universidad de Sevilla, Avda. Americo Vespucio s/n, E-41092 Seville, Spain. aurelio@cica.es
authors.forename: Aurelio
authors.initials: A
authors.lastname: Serrano
authors.forename: Jose R
authors.initials: JR
authors.lastname: Perez-Castiñeira
authors.forename: Herrick
authors.initials: H
authors.lastname: Baltscheffsky
authors.forename: Margareta
authors.initials: M
authors.lastname: Baltscheffsky
mesh_terms: D000595:Amino Acid Sequence; D001105:Archaea / Q000201:enzymology*; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology*; D004789:Enzyme Activation; D004795:Enzyme Stability; D043564:Inorganic Pyrophosphatase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D008968:Molecular Conformation; D008969:Molecular Sequence Data; D011387:Prokaryotic Cells / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013696:Temperature
chemical_list: D043564:Inorganic Pyrophosphatase