摘要
鱼类抗菌肽是鱼体天然免疫的重要组成部分 ,其结构和组成复杂多样 .根据生化和结构特点 ,可将它们分为 4种基本类型 :具有疏水或双亲性α螺旋结构的抗菌肽、含多对二硫键并可形成 β折叠结构的抗菌肽、组蛋白样抗菌肽和具有糖基化修饰的抗菌肽 .鱼类抗菌肽多以前肽原的形式合成 ,通过酶解切除信号肽和羧基端酸性片段后形成有活性的成熟肽 .成熟肽具有很强的抑菌活性 ,其最小抑制浓度多在毫摩尔水平 .目前 ,已克隆了多个鱼类抗菌肽基因 ,揭示了pleurocidin等基因家族的结构及其转录调控特点 .鱼类抗菌肽的抗菌机制已建立了“桶 桶板”和“地毯”样两种模型 。
Many fishes produce a repertoire of positively charged antibacterial peptides as part of innate immunity to bacterial invasion. Based on their biochemical and structural properties, fish antibacterial peptides can be classified into four types: amphipathic or hydrophobic alpha-helical peptides without cysteine; beta-sheet peptides with several disulfides bonds; histone-like proteins and glycoproteins. Despite significant variations in length and composition, a common feature of fish antibacterial peptides is that they all have special structures which allow them to bind or disturb the membrane of bacteria in millimolar concentrations. Fish antibacterial peptides are predicted to be translated as prepropeptides that undergo proteolytic cleavage of amino-terminal hydrophobic signal and carboxy-terminal acidic portion to form the mature peptides. Heretofore, several fish antibacterial peptide genes have been cloned and sequencing analyses revealed that most of them were comprised of an open reading frame with four exons and three introns and the upstream region with some consensus binding sequences for transcription factors found in other fish functional genes. Recent data suggest that the details of the antibacterial pathways may vary for different peptides and are assigned to different mechanisms. Some may kill bacteria by forming transmembrane ion channels according to the 'barrel-stave' mechanism, and some by disrupting membrane according to the 'carpet-like' mechanism. In addition, alternative mechanisms, which include their binding to DNA and their interference with DNA or protein synthesis, have been proposed to explain the antibacterial action of several peptides. The study of fish antibacterial peptides, may improve the understanding of peptide-mediated host defence.
出处
《生物化学与生物物理进展》
SCIE
CAS
CSCD
北大核心
2002年第5期682-685,共4页
Progress In Biochemistry and Biophysics
关键词
鱼类抗菌肽
研究进展
分子结构
基因克隆
抗菌机制
生物学活性
fish antibacterial peptides
molecular structure
gene cloning
antibacterial mechanism
biological activity
