title: Identification of angiotensin I in several vertebrate species: its structural and functional evolution.
abstract: In order to delineate further the molecular evolution of the renin-angiotensin system in vertebrates, angiotensin I (ANG I) has been isolated after incubation of plasma and kidney extracts of emu (Dromiceus novaehollandiae), axolotl (Ambystoma mexicanum), and sea lamprey (Petromyzon marinus). The identified sequences were [Asp1, Val5, Asn9] ANG I in emu, [Asp1, Val5, His9] ANG I in axolotl, and [Asn1, Val5, Thr9] ANG I in sea lamprey. These results confirmed the previous findings that tetrapods have Asp and fishes including cyclostomes have Asn at the N-terminus, and that the amino acid residue at position 9 of ANG I was highly variable but, those at other positions were well conserved among different species. Since Asp and Asn are convertible during incubation, angiotensinogen sequences were searched in the genome and/or EST database to determine the N-terminal amino acid residue from the gene. The screening detected 12 tetrapod (10 mammalian, one avian, and one amphibian) and seven teleostean angiotensinogen sequences. Among them, all tetrapods have [Asp1] ANG except for Xenopus, and all teleosts have [Asn1] ANG, thereby confirming the above rule. Comparison of the vasopressor activity in the eel revealed that [Asn1] ANG I and II were more potent than [Asp1] peptides, which was opposite to the previous results in mammals and birds, in which [Asp1] ANG I and II were more potent. Collectively, the present results support the general rule that tetrapods have [Asp1] ANG and fishes including cyclostomes have [Asn1] ANG. However, an aquatic anuran (Xenopus) has [Asn1] ANG in its gene despite another aquatic urodele (axolotl) has [Asp1] ANG. From the functional viewpoint, homologous [Asn1] ANG was more potent in fish as is homologous [Asp1] ANG in tetrapods, suggesting that ANG II molecule has undergone co-evolution with its receptor during vertebrate phylogeny.
authors.affiliation: Ocean Research Institute, University of Tokyo, 164-8639, Japan. takei@ori.u-tokoyo.ac.jp
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Takei
authors.forename: Jean M P
authors.initials: JM
authors.lastname: Joss
authors.forename: Werner
authors.initials: W
authors.lastname: Kloas
authors.forename: J Cliff
authors.initials: JC
authors.lastname: Rankin
mesh_terms: D000557:Ambystoma / Q000235:genetics; D000595:Amino Acid Sequence; D000803:Angiotensin I / Q000032:analysis / Q000235:genetics* / Q000494:pharmacology; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002845:Chromatography; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D020312:Dromaiidae / Q000235:genetics; D004524:Eels / Q000502:physiology; D019143:Evolution, Molecular; D007668:Kidney / Q000737:chemistry; D007798:Lampreys / Q000235:genetics; D013058:Mass Spectrometry; D017386:Sequence Homology, Amino Acid; D014020:Tissue Extracts / Q000737:chemistry / Q000378:metabolism; D014714:Vertebrates / Q000235:genetics*
chemical_list: D014020:Tissue Extracts; D000804:Angiotensin II; D000803:Angiotensin I