结核分枝杆菌FadD3结构与功能的生物信息学分析

Bioinformatic analysis of the structure and function of FadD3 from Mycobacterium tuberculosis

目的应用生物信息学分析软件预测结核分枝杆菌脂酰辅酶A合成酶(FadD3)氨基酸序列的结构与功能。方法应用生物信息学在线工具NCBI(http://www.ncbi.nlm.nih.gov/)、Expasy(http://ca.expasy.org/)、SWISSMODEL(http://swissmodel.expasy.org/)、客户端软件clustalx等进行多重序列比较、同源性分析、同源模建及蛋白功能活性位点分析;应用ProtParam软件(http://web.expasy.org/protparam)预测FadD3基因编码FadD3的蛋白理化性质;采用最小值进化法(the Minimum Evolution method)构建分子进化树。结果 FadD3(Mt-FACS)与其他物种的脂酰辅酶A合成酶(FACS)含相同的保守序列及催化活性位点,第174-185氨基酸残基是AMP结合部位,也是FadD3的保守区域;第422-497氨基酸残基是FACS与底物(脂酸)结合的部位,亦是结核分枝杆菌脂酰辅酶A合成酶的C末端。分子进化分析表明结核分枝杆菌脂酰辅酶A合成酶(Mt-FACS)与睾丸酮丛毛单胞菌脂酰辅酶A合成酶(CtFACS)的进化关系较近,与黑腹果蝇脂酰辅酶A合成酶(Dm-FACS)的进化关系较远。结论生物信息学预测提示FadD3是结核分枝杆菌脂类代谢及耐药性研究的潜在靶蛋白。

Objective To use bioinformatic software to predict the structure and function of a fatty acyl-CoA synthetase（FadD3）from Mycobacterium tuberculosis. Methods Multiple sequence alignment,analysis of homology,modeling of homology,and analysis of the active sites of proteins were performed with the help of online tools such as NCBI（http：//www.ncbi.nlm.nih.gov/）,Expasy（http：//ca.expasy.org/）,and SWISSMODEL（http：//www.swissmodel.expasy.org/）and client software like Clustalx.The physicochemical properties of the synthetase encoded by the FadD3 gene were predicted using the software ProtParam（http：//web.expasy.org/protparam）.A molecular phylogenetic tree was constructed using the minimum evolution method. Results Results indicated that FadD3 had the same conserved sequences as FadD3（Mt-FACS）and fatty acyl-CoA synthetases（FACS）from other species and key catalytic sites such as Thr177,Gly179,Thr180,Thr181,Gly182,Lys185,Glu426,Glu428,and Val443.Amino acid residues 174-185 are AMP binding sites and that region is conserved in FadD3.Amino acid residues 422-497 are binding sites that bind FACS and its substrate（a fatty acid）.Highlighted is the C-terminal domain of Mt-FACS.Phylogenetic analysis revealed that M.tuberculosis（Mt-FACS）and Comamonas testosteroni（Ct-FACS）share a closer evolutionary relationship than do MtFACS and Drosophila melanogaster（Dm-FACS）. Conclusion Bioinformatic prediction indicated that FadD3 might be a potential target protein for research on lipid metabolism in and the drug resistance of M.tuberculosis.