title: Nine novel precursors of Buthus martensii scorpion alpha-toxin homologues.
abstract: The cDNAs encoding nine novel alpha-toxin homologues were isolated from the venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch (BmK). They are rich in AAAA and TTTT elements at the 5' UTRs. The flanking region of the translation initiation codon ATG is AAAATGAA, which is highly conserved in scorpion Na(+), K(+) and Cl(-) channel toxin genes. These putative scorpion alpha-toxins shared 45.5-98.4% homology with the characterized BmK alpha-toxins, and were completely conserved in the positions of all eight cysteines. This showed, together with higher homology at nucleotide level than that at amino acid level, that these toxins may originate from a common ancestor. The discovery of a series of homologues of scorpion alpha-toxin with a different degree of natural mutation in the primary structure will provide us with a valuable system for studying the structure-function relationship of scorpion toxins.
authors.affiliation: Department of Biotechnology, College of Life Sciences, Wuhan University, 430072, Wuhan, People's Republic of China. shunyizhu@hotmail.com
authors.forename: S Y
authors.initials: SY
authors.lastname: Zhu
authors.forename: W X
authors.initials: WX
authors.lastname: Li
authors.forename: X C
authors.initials: XC
authors.lastname: Zeng
authors.forename: H
authors.initials: H
authors.lastname: Liu
authors.forename: D H
authors.initials: DH
authors.lastname: Jiang
authors.forename: X
authors.initials: X
authors.lastname: Mao
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000302:isolation & purification; D019143:Evolution, Molecular; D005088:Exocrine Glands / Q000378:metabolism*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals / Q000235:genetics*; D012333:RNA, Messenger / Q000302:isolation & purification; D012604:Scorpion Venoms / Q000235:genetics* / Q000302:isolation & purification; D012605:Scorpions; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D021382:Protein Sorting Signals; D012333:RNA, Messenger; D012604:Scorpion Venoms