寡发酵链球菌乳酸脱氢酶蛋白质结构的预测  

Protein structure prediction of the lactate dehydrogenase of Streptococcus oligofermentans

作　　者：肖瑶[1,2] 岳林[1] 

机构地区：[1]北京大学口腔医学院·口腔医院牙体牙髓科,100081 [2]北京大学口腔医学院·口腔医院第一门诊部,100034

出　　处：《中华口腔医学杂志》2013年第10期591-595,共5页Chinese Journal of Stomatology

基　　金：北京市自然科学基金（7102163）

摘　　要：目的 探讨寡发酵链球菌和口腔中不同产酸能力的细菌乳酸脱氢酶（lactatedehydrogenase,LDH）基因序列和蛋白质各级结构的差异,为进一步研究寡发酵链球菌糖代谢的生化机制提供依据.方法 寡发酵链球菌LDH的基因序列由中科院微生物所测出.通过美国国家生物技术信息中心的Genbank数据库查找变形链球菌、血链球菌和干酪乳杆菌LDH的基因序列,用BLAST软件对各细菌LDH的基因序列和氨基酸序列进行比对.采用蛋白分析专家系统（Expert Protein Analysis System,ExPASy）对寡发酵链球菌、变形链球菌、血链球菌和干酪乳杆菌LDH蛋白质的理化性质、二级结构、结构域和空间结构进行预测并比较.结果 寡发酵链球菌LDH的基因序列共987个碱基对,与血链球菌相似性最高（89％）,与变形链球菌的相似性为81％,与干酪乳杆菌相似性最低（70％）；寡发酵链球菌LDH氨基酸序列与血链球菌的相似性高达96％,与变形链球菌相似性较低（86％）,与干酪乳杆菌的相似性仅为66％；寡发酵链球菌LDH蛋白质的理化性质、跨膜区数目、二级结构的比例、结构域位置与其他3种细菌均相近,LDH的空间结构与变形链球菌、干酪乳杆菌明显不同,与血链球菌也有差异.结论 寡发酵链球菌LDH在基因序列、氨基酸序列及空间结构上与变形链球菌和干酪乳杆菌的差异,可能是导致其LDH生物学功能改变,不能产生乳酸的一个内在原因.Objective To compare the gene sequence and protein structure of lactate dehydrogenase （LDH） in Streptococcus oligofermentans with those of other bacteria with different acid generating capacities in oral cavity and to analyze the differences of their LDH.Methods LDH gene sequence of Streptococcus oligofermnentans was measured by Institute of Microbiology,Chinese Academy of Sciences.LDH gene sequences of four Streptococcus and Lactobacillus casei in the NCBI Genbank was identified and compared among the six bacteria＇s LDH gene sequences and amino acid sequences by BLAST software.ExPASy database was used to predict the physical-chemical characteristics,secondary structure,trans-membrane regions,and spatial structure of Streptococcus oligofermentans LDH protein,which was compared with those of other bacteria.Results The fulllength of the LDH gene sequences of Streptococcus oligofermentans was 987 base pairs.The highest similarity was 89% with that of the Streptococcus sanguis,and 81% similarity with Streptococcus mutans,and 70% similarity with Lactobacillus cusei.LDH amino acid sequence of Streptococcus oligofermentans was similar to Streptococcus sanguinis,with the highest similitude of 96%,with a similitude of 81% to Streptococcus mutans,but differed greatly from that of Lactobacillus cusei,with a similitude of only 66%.Streptococcus oligofermentans LDH protein＇s physical-chemical characteristics,trans-membrane region＇s numbers,proportions of secondary structure,structural domain＇s location resembled those of Streptococcus mutans,Streptococcus sanguinis and Lactobacillus cusei.Spatial structure differences between the LDH of Streptococcus oligofermentans and that of Streptococcus mutans and Lactobacillus casei were distinct.Conclusions Streptococcus oligofermentans LDH＇s gene sequence,amino acid sequence,and spatial structure all vary from those of Streptococcus mutans and Lactobacillus casei,and these differeces may be a inherent reason that lead to the changes of its LDH＇s biological functions an

关 键 词：寡发酵链球菌 乳酸脱氢酶 蛋白质结构预测 

分 类 号：R780.2[医药卫生—口腔医学]