摘要
目的了解天津地区人偏肺病毒（hMPV）G蛋白特性，为深入研究（hMPV）奠定基础。方法采用RT—PCR方法扩增hMPV的G基因片段，测序后通过生物信息学软件分析核苷酸同源性，绘制种系发生树，并对推导的G蛋白氨基酸序列的糖基化位点、跨膜序列及二级结构进行预测。结果天津地区hMPVG蛋白由217～238个氨基酸组成。种系发生树分析显示，hMPV可分为A2a、A2b和B23个亚型，A2b为优势流行型。A2亚型内的核苷酸同源性在90．1％～99．5％，推导的氨基酸同源性在80．4％～99．1％；A、B亚型之间核苷酸同源性为57．4％～60．3％，推导的氨基酸同源性为30．3％～37．1％。hMPVG蛋白的S和T总含量在30．9％～34．0％之间，A和B型间差异无统计学意义（P〉0．05）。N-糖基化位点在2～6之间。10株A2亚型hMPVG蛋白的跨膜区为N-端33～55位氨基酸，1株B2亚型hMPVG蛋白为N-端27-49位氨基酸。G蛋白氨基酸变异多发生在膜外区。二级结构预测显示，柔性结构占G蛋白氨基酸总数的62．7％～84．1％，其中以无规则卷曲为主，占60．8％～84．1％。该区域也多集中在膜外区，成为抗原表位的可能性较大。结论天津地区hMPV的优势流行型为A2b，其G蛋白特性有地区流行特点。
Objective To understand the characteristics of human metapneumovirus （hMPV） G proteins in Tianjin and to lay the foundations for further study. Methods The G gene fragments of hMPV were amplified by RT-PCR. After sequencing, the identities of nucleotides were determined and amino acids were deduced, a phylogenetic tree was constructed, and glycosylation sites, transmembrane helices, and secondary structures of G proteins were predicted using different software packages. Results G proteins of hMPV in Tianjin consisted of 217--238 amino acids. A2a, A2b, and B2 subtypes were present in Tianjin, and A2b was the predominant subtype. Nucleotide and deduced amino acid similarities within the A2 subtype were 90.1%--99.5% and 80.4% --99.1%, respectively, while nucleotide and amino acid similarities between A2 and B2 were 57.4%--60.3% and 30.3%--37.1%. S and T content was 30.9%--34.0%, and there was no difference between types A and B （P〉0.05）. There were 2--6 potential N-linked glycosylation sites in the G protein. The transmembrane domain predicted in 10 A2a subtype hMPV G proteins was at amino acids at positions 33--55 at the N-terminal and another B2 subtype strain （TJ08--01） was at positions 27--44. Most variation in the G protein was located in the outer membrane domain. The flexible regions, mostly coil regions （60.8 %- 84.1% ）, were the main structure type in secondary structures predicted in G proteins, accounting for 62.7 %- 84.1% of all amino acids. These flexible regions were predominantly located in the outer membrane domain and were more likely to be antigenic epitopes. Conclusion A2b was the most prevalent hMPV subtype in Tianjin. G proteins of hMPV in Tianjin had their own regional characteristics.
出处
《中国病原生物学杂志》
CSCD
2010年第1期6-10,共5页
Journal of Pathogen Biology
基金
天津市科技支撑重大项目(No.07SYSYSF05100)
天津市卫生局资助课题(No.05KY25)
关键词
人偏肺病毒
G蛋白
种系发生分析
二级结构
Human metapneumovirus
G protein
phylogenetic analysis
secondary structure
