c血清型变形链球菌低毒力株特异DNA片段的生物信息学分析

Bioinformatical analysis of avirulent strain-specific DNA fragments from Streptococcus mutans of serotype c

目的：发现c血清型变形链球菌低毒力株特异的新基因或已知基因的新功能，推测、鉴定基因所编码蛋白质的功能。方法：对筛选得到的26个变形链球菌低毒力株特异的DNA片段进行序列测定，利用BLAST2．2．6程序进行核苷酸和含6相位阅读框架编码氨基酸的相似性检索。结果：变形链球菌低毒力株特异的DNA片段大小在113～776bp之间，平均G＋C含量为38．27％，其中有8个片段为新的基因片段，在GenBank中登记。结论：发现了8个新的基因片段以及低毒力株特异的DNA片段的主要功能，为下一步的基因功能研究奠定基础。

Objective：To explore avirulent strain-specific new genes or new functions of already known genes from Streptococcus mutans of serotype c. Methods：Twenty-six DNA fragments unique to avirulent strain of Streptococcus mutans were sequenced. The sequences of these presumptive avirulence DNA fragments were subjected to homology search through BLASTn and BLASTx in public database, and their putative biological functions were analyzed. Restilts ：The size of the DNA fragments ranged from 113 bp to 776 bp. The average G ＋ C content was 38.27% , similax to that of the gene-codingsequences in Streptococcus mutans strain UAI59 whose genome sequences were just completed. Seven clones were picked repeatedly. Of the nineteen DNA fragments, eight potentially represented new DNA fragments were registered in GenBank. The remaining DNA fragments showed high homology to known genes of Streptococcus mutans strain UA159. Conclusions： The gene analysis and identification supply the groundwork for further study of gene functions of the avirulent strain of Streptococcus mutans serotype c.