恙虫病东方体Ot56蛋白序列生物信息学分析

Bioinformatics Analysis of Ot56 Protein in Orientia tsutsugamushi

目的分析恙虫病东方体Ot56蛋白序列中的变异区和保守区,为恙虫病的蛋白与核酸诊断提供参考。方法从GenBank获取目标序列,用Lasergene、MEGA、Vector NTI suite、AthePort和NCBI Blast等工具进行分析。结果120条Ot56氨基酸序列的相似性为61.4%～100.0%,变异度为0.0～57.1;氨基酸的105～171、179～215、248～285、375～428和447～503区域为高变异区;膜外区200～400具有变异度高、抗原性强的特性。113条Ot56cDNA序列的相似性为41.8%～100.0%,变异度为0.0～116.1;其中303～481、562～667、756～842、1136～1243和1386～1568等5个区域属高变异区,而0～54、97～171、265～303、439～482、1015～1047和1477～1542为6个保守片段。结论恙虫病东方体Ot56蛋白具有5个高变异区,第200～400位氨基酸附近可能是株(型)特异性表位所在区域,其重组蛋白具有潜在的株(型)鉴定价值。根据cDNA6个保守片段设计引物,进行Ot56核酸检测可能在不同株(型)恙虫病东方体检测中具有较高的敏感性。

Objective To analyze the conserved and variable regions of a 56 000 Mr protein of Orientia tsutsugarnushi （Ot56） for diagnosis of scrub typhus. Method The sequence of 120 peptides and 113 cDNA derived from Orientia tsutsugarnushi were analyzed by Lasergene suite, Vector NTI suite, MEGA, AthePort and NCBI Blast. Result The similarity of the peptide sequence was ranged from 61.4% to 100.0% ,and the variability was ranged from 0 to 57.1. Five variable regions, namely aa105-171, 179-215, 248-285, 375-428 and 447-503, were identified. The sequence of aa 200-400 in the ecto domain is highly variable and antigenic. For the 113 cDNA, the percentage of similarity was ranged from 41.8% to 100%, and the variability was ranged from 0.0 to 116.1. Five highly variable regions at 303-481, 562-667, 756-842, 1136-1243 and 1386-1568; and 6 conserved regions at 0-54, 97-171, 265-303, 439-482, 1015-1047 and 1477-1542 were identified. Conclusion The Ot56 protein has 5 highly variable regions. Sequence of aa 200-400 is highly variable and antigenic. There are 6 conserved regions in the cDNA of Ot56. PCR primers for these conserved regions may be used in the clinical diagnosis of scrub typhus.