浑球红细菌谷氨酰胺合成酶基因(glnA)及PⅡ蛋白基因(glnB)的序列分析  

Nucleotide Sequences of glnB and glnA Genes from Rhodobacter sphaeroides

作　　者：韩涛 吴永强[1] 宋鸿遇[1] 

机构地区：[1]中国科学院上海植物生理研究所,上海200032

出　　处：《植物生理学报（0257-4829)》1997年第2期130-138,共9页Acta Phytophysiologica Sinica

基　　金：国家科委"863"生物高技术资助

摘　　要：测定了浑球红细菌的glnA和／glnB基因DNA序列，共2707nt。其中glnA基因编码区为1401nt，编码467个氨基酸；glnB基因编码区为336nt，编码112个氨基醚。DNA序列的G＋C百分含量为65％，它们的密码子第三位GC利用率高达89．1％。在氨基酸序列上，GS酶和PⅡ蛋白与其它不同属的细菌间有较好的同源性，尤其是固氮类细菌间同源性较高。Complete nucleotide sequences ofthe glnA gene (structural gene for glutamine synethase) and glnB gene (structural gene for P 11 protein ) from thepurple non-sulphur photosynthetic bacterium Rhodobacter sphaeroides were determined (Fig. 2). The glnA gene is composed of 1 401 nt and is correspondingto 467 amino acid residues; the glnBgene is composed of 336 nt, which encode a 1 12 residue polypeptide. The GCcontent of the 2 707 nt DNA sequenceis 65%, which is close to the total GCcontent of R. sphaeroides. The probability of GC on third position of the codonis 89. 1 % (Table 1 ). Comparison ofthe deduced amino acid sequences of GSand P E protein from R. sphaeroideswith those from other bacteria separately suggests that the GS protein of R.sphaeroides is more similar to the GS proteins from nitrogen fixation bacteriathan that of the enteric bacteria, but thehomological parts of P Ⅱ protein between these kinds of bacteria are verysimilar. And we found the same sequence 5' AAAGGG3' upstream thetwo ORFs of the gln A and gln B genes,which were suspected as the ribosomebinding site (RBS ) (Fig. 2 ). But wehave not found any E. call-like promoter sequence upstream the gin A and gin Bgenes of the R. sphaeroides. There aresome inverted repeated sequencs, thesesequences might play a regulatory rolein the course of transcription of glnB andglnA gene.

关 键 词：浑球红细菌 谷氨酰氨合成酶 基因 glnB基因 固氮 

分 类 号：Q945.13[生物学—植物学]