人防御素5研究进展

Research Progress on Human Defensin 5

目的 探讨人防御素 5 (humandefensin 5 ,HD 5 )的分子结构、抗菌活性、基因表达等特点 ,展望HD 5作为抗肠源性感染新药的开发前景。方法 采用文献回顾的方法对有关HD 5研究资料进行综合比较和综述。结果 HD 5是一种不含糖链的碱性阳离子多肽 ,相对分子质量为 ( 3～ 5 )× 10 3 ,成熟肽由 32个氨基酸残基组成 ,富含精氨酸、半胱氨酸 ;分子内含有 3对由半胱氨酸形成的二硫键 ,并以此行使其对革兰氏阳性菌、革兰氏阴性菌、真菌、螺旋体、原生动物、有包膜病毒等的抗菌功能。HD 5的编码基因DEFA5位于第 8条染色体P2 1 pter区 ,全长4 4 9bp。其中 1～ 4 0为 5′端非翻译区 ,4 1～ 97为信号肽序列 ,98～ 2 2 6编码HD 5前片段 ,2 2 7～ 32 2为HD 5成熟肽编码序列 ,PolyA序列位于 4 33～ 4 38。 结论 HD 5是一种广谱、高效、不产生耐药性的内源性抗微生物小分子肽 ,如能解决其大量生产的难点 。

Objective To review the characteristics of human defensin 5 (HD 5), including molecular structure, antibacterial activity and gene expression, and to show its development prospect as a new drug in the treatment of enterogenic infection. Methods The published papers about HD 5 were reviewed to summarize its research progress. Results Being a 3-5 KDa cationic peptide rich in cysteine and arginine, especially without glycosylated side chain, HD 5 plays its antibacterial role against positive and negative Gram's bacterium, fungi, spirochete, protozoan and enveloped virus with the special active center composed of three disulfide bonds. HD 5 encoding gene alpha defensin 5 (DEFA 5) localizes at the 8th chromosome P21 pter with 449 bp, which includes five pieces of sequence: 5′ untranslated region (1-40),signal peptide (41-97), propiece (98-226), mature peptide (227-322),and Poly A (433-438).Conclusion As a broad spectrum and effective endogenous antimicrobial peptide, HD 5 would be a promising alternative peptide against enterogenic infection if the accessibility to its mass production is settled.