title: Characterization of metallothioneins (MT-I and MT-II) in the yak.
abstract: The cDNA-encoding sequences for yak metallothionein isoforms I (MT-I) and II (MT-II) were amplified and cloned by reverse-transcription PCR to characterize the nucleotide sequence and protein structure of metallothionein in the yak. The cDNA sequences of MT-I and MT-II were subjected to BLAST searching at the National Center for Biotechnology Information, and the results indicated that the nucleotide sequences of yak MT-I and MT-II, when compared among different species of mammals, are highly conserved. The yak open reading frames have a length of 183 nucleotides, which encode for yak MT-I and MT-II proteins of 61 AA, respectively. Analysis of hydrophobicity, trans-membrane region, and signal peptides suggested that metallothioneins of the yak are nonsecretory proteins. There were several conserved tripeptide sequences, such as C-X-C, C-C-X-C-C, and C-X-X-C (X designates AA excluding cysteine in MT-I and MT-II), and they are highly conserved in their evolution. By homologous comparative modeling, we predicted the molecular spatial structures of yak MT-I and MT-II, which are composed of alpha- and beta-domains that are linked by the conserved tripeptide Lys(30)-Lys(31)-Ser(32) (KKS).
authors.affiliation: College of Animal Science and Technology, Gansu Agricultural University, Lanzhou, China 730070. wujp@gsau.edu.cn
authors.forename: J P
authors.initials: JP
authors.lastname: Wu
authors.forename: B Y
authors.initials: BY
authors.lastname: Ma
authors.forename: H W
authors.initials: HW
authors.lastname: Ren
authors.forename: L P
authors.initials: LP
authors.lastname: Zhang
authors.forename: Y
authors.initials: Y
authors.lastname: Xiang
authors.forename: M A
authors.initials: MA
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D018076:DNA, Complementary; D008668:Metallothionein / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data
chemical_list: D018076:DNA, Complementary; D008668:Metallothionein