tailieunhanh - Báo cáo Y học: Novel bradykinins and their precursor cDNAs from European yellow-bellied toad (Bombina variegata) skin

Two novel bradykinin-related peptides (Ala3,Thr6)-bra-dykinin and (Val1,Thr3,Thr6)-bradykinin, were identified by a systematic sequencing study of peptides in the defensive skin secretion of the yellow-bellied toad,Bombina variegata. These peptides are the first amphibian skin bradykinins to exhibit amino acid substitutions at the Pro3 position of the bradykinin nonapeptide. | Eur. J. Biochem. 269 4693-4700 2002 FEBS 2002 doi Novel bradykinins and their precursor cDNAs from European yellow-bellied toad Bombina variegata skin Tianbao Chen1 2 David F. Orr1 Anthony J. Bjourson1 Stephen McClean1 Martin O Rourke1 David G. Hirst1 Pingfan Rao2 and Chris Shaw1 1 School of Biomedical Sciences University of Ulster Coleraine Northern Ireland UK 2The Institute of Biotechnology Fuzhou University Fujian Province People s Republic of China Two novel bradykinin-related peptides Ala3 Thr6 -bra-dykinin and Val1 Thr3 Thr6 -bradykinin were identified by a systematic sequencing study of peptides in the defensive skin secretion of the yellow-bellied toad Bombina variegata. These peptides are the first amphibian skin bradykinins to exhibit amino acid substitutions at the Pro3 position of the bradykinin nonapeptide. Previously reported bradykinins from other Bombina species were not detected. Respective precursor cDNAs designated BVK-1 and BVK-2 respectively were cloned from a skin library by 3 - and 5 -RACE reactions. BVK-1 contained an open-reading frame of 97 amino acids encoding a single copy of Ala3 Thr6 -brady-kinin and similarly the open-reading frame of BVK-2 consisted of 96 amino acids encoding a single copy of Val1 Thr3 Thr6 -bradykinin. Synthetic replicates of each novel bradykinin were found to be active on mammalian arterial and small intestinal smooth muscle preparations. The structural diversity of bradykinins in amphibian defensive skin secretions may be related to defence against specific predators. Keywords amphibian bradykinin skin precursor cloning. The skins of anuran amphibians in addition to mucous glands contain highly specialized poison glands which in reaction to stress or attack exude a complex noxious cocktail of biologically active molecules 1 . These secretions often contain a plethora of peptides among which bradykinin or structural variants have been identified 2-5 . The kallikrein-kininogen .