Archaerhodopsin-2, from Halobacterium sp. aus-2 further reveals essential amino acid residues for light-driven proton pumps.
We have isolated a retinal protein which differs from bacteriorhodopsin and archaerhodopsin and pumps out as many protons in the light as those proton pumps. We tentatively named it archaerhodopsin-2. We have cloned and sequenced the gene that encodes archaerhodopsin-2. The gene consists of 780-bp nucleotides for 259 amino acids with a molecular mass of 27,937 Da. The amino acid sequence of archaerhodopsin-2 is 56% identical to bacteriorhodopsin and 88% to archaerhodopsin, with a few gaps of a few amino acids in both cases. Although the amino acid sequence of archaerhodopsin has revealed 157 conserved residues common to bacteriorhodopsin, the sequence of archaerhodopsin-2 reduces that number to 133. Of these, 38 amino acids are also common to chloride pumps and 24 to all bacterial retinal proteins known to date.
Uegaki
K
K
Department of Biology, Faculty of Science, Nagoya University, Japan.
Sugiyama
Y
Y
Mukohata
Y
Y
D000595:Amino Acid Sequence; D019843:Archaeal Proteins; D001426:Bacterial Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D001483:Base Sequence; D002462:Cell Membrane / Q000378:metabolism; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D005798:Genes, Bacterial; D006217:Halobacterium / Q000235:genetics / Q000378:metabolism*; D008027:Light; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011522:Protons; D012168:Retinal Pigments / Q000235:genetics; D012689:Sequence Homology, Nucleic Acid; D017494:Proton Pumps
D019843:Archaeal Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D011522:Protons; D012168:Retinal Pigments; C055476:archaerhodopsin protein, Archaea; D017494:Proton Pumps