植物乳杆菌LY-78乳酸脱氢酶基因的生物信息学分析

摘要

目的:探究植物乳杆菌LY-78菌株全部5个乳酸脱氢酶基因及其编码蛋白质的结构和功能.方法:应用多种生物信息学软件对植物乳杆菌LY-78菌株的5个乳酸脱氢酶基因及氨基酸序列进行结构分析和功能预测.结果:植物乳杆菌LY-78中5个乳酸脱氢酶的核苷酸及氨基酸序列均具有较高的保守性,均为位于细胞质的热稳定性、非分泌、非跨膜蛋白,除了ldhL3基因,其余4个基因均具有各自高度保守的功能位点和结构域,均存在典型的烟酰胺腺嘌呤二核苷酸(nicotinamide adenine dinucleotide,NAD+)结合位点序列GXGXXG.结论:乳酸脱氢酶D1 (D1-lactate dehydrogenase,D1-LDH)、D2-LDH、L1-LDH及L2-LDH均具有完整的功能位点和结构域,很可能具有真正的乳酸脱氢酶活性,L3-LDH由于缺失NAD+结合结构域和功能位点,因而可能不具有乳酸脱氢酶活性,这些分析结果为今后植物乳杆菌乳酸脱氢酶基因改造和苯乳酸合成代谢机制研究提供了必要的理论基础.%Objective:To explore the structure and function of the five lactate dehydrogenase genes and their encoded proteins from Lactobacillus plantarum LY-78.Methods:Several bioinformatic tools were used to analyze and predict the gene sequences and amino acid sequences of lactate dehydrogenase from the strain.Results:The nucleotide and amino acid sequences of the five lactate dehydrogenases in L.plantarum LY-78 were all highly conserved.The five lactate dehydrogenase proteins showed thermal stability and were non-secretory and non-transmembrane proteins,which were located in the cytoplasm.All the four genes except ldhL3 had highly conserved functional sites and domains,and contained the highly conserved sequence GXGXXG,which had typical NAD+ binding sites.Conclusion:D1-LDH,D2-LDH,L1-LDH and L2-LDH manifest complete functional sites and domains,likely having a real activity of lactate dehydrogenase.Because of the lack of NAD+ binding domain and functional sites,L3-LDH may not have lactate dehydrogenase activity.These results are important for theoretical researches of genetic modification of the lactate dehydrogenase genes and the metabolic mechanism of phenyllactic acid in L.plantarum LY-78.