Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad an...Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.展开更多
The epididymal β-defensins have evolved by repeated gene duplication and divergence to encode a family of proteins that provide direct protection against pathogens and also support the male reproductive tract in its ...The epididymal β-defensins have evolved by repeated gene duplication and divergence to encode a family of proteins that provide direct protection against pathogens and also support the male reproductive tract in its primary function. Male tract defensins also facilitate recovery from pathogen attack. The β-defensins possess ancient conserved sequence and structural features widespread in multi-cellular organisms, suggesting fundamental roles in species survival. Primate SPAG11, the functional fusion of two ancestrally independent β-defensin genes, produces a large family of alternatively spliced transcripts that are expressed according to tissue-specific and species-specific constraints. The complexity of SPAG11 varies in different branches of mammalian evolution. Interactions of human SPAG11D with host proteins indicate involvement in multiple signaling pathways. （Asian J Andro12007 July; 9： 453- 462）展开更多
文摘Defensin is a kind of cationic, inducible antimicrobial peptide found in a large range of living organisms that contributes to host defense by disrupting the cytoplasmic membrane of microorganisms. With their broad antimicrobial spectrum and strong pharmaceutical effects, antimicrobial peptides, including defensins, represent a source of novel antibiotic agents. A novel full-length 430 base pairs cDNA of an insect defensin was cloned using polymerase chain reaction (PCR) from the cDNA library of houseflies (Musca domestica) that had been challenged by E. coli and Staphylococcus aureus. Sequence analysis revealed that the open reading frame of the cDNA encoded a 92-amino acid peptide, which contained an NH 2-terminal signal sequence (1-22) followed by a propeptide and the mature peptide (53-92). The sequence identity with other insect defensin is between 51% and 73%. The mature peptide, with a predicted molecular weight of 4\^0 kDa, and pI of 8\^69, has 1 negative charged amino acid and 4 positice ones. The putative housefly defensin is characterized by 6 invariant cysteine residues forming 3 disulfide bonds, Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6. These results suggest that the novel full-length cDNA of the defensin gene, denominated Mdde, has been successfully cloned from houseflies.
文摘The epididymal β-defensins have evolved by repeated gene duplication and divergence to encode a family of proteins that provide direct protection against pathogens and also support the male reproductive tract in its primary function. Male tract defensins also facilitate recovery from pathogen attack. The β-defensins possess ancient conserved sequence and structural features widespread in multi-cellular organisms, suggesting fundamental roles in species survival. Primate SPAG11, the functional fusion of two ancestrally independent β-defensin genes, produces a large family of alternatively spliced transcripts that are expressed according to tissue-specific and species-specific constraints. The complexity of SPAG11 varies in different branches of mammalian evolution. Interactions of human SPAG11D with host proteins indicate involvement in multiple signaling pathways. （Asian J Andro12007 July; 9： 453- 462）
