Wu L F, Saier M H
Department of Biology, University of California, San Diego, La Jolla 92093-0116.
Res Microbiol. 1991 Nov-Dec;142(9):943-9. doi: 10.1016/0923-2508(91)90004-t.
Codon usage in Rhodobacter was evaluated and found to be strikingly different from that in Escherichia coli. While codon usage for genes concerned with nitrogen utilization and carotenoid biosynthesis corresponded to expectation, based on codon usage for Rhodobacter in general, that for the fructose utilization (fru) operon and for the photosynthetic genes encoding the reaction centre and light harvesting proteins exhibited significant deviation from expectation and from each other for specific amino acids. The differences in codon usage for the fru operon versus the photosynthetic genes may reflect different proportions of the various tRNA specific for certain amino acids when cells are grown under heterotrophic versus phototropic conditions. In addition, preferential use of the initiation codon, GTG, was found for the first cistrons of Rhodobacter operons.
对红细菌的密码子使用情况进行了评估，发现其与大肠杆菌的密码子使用情况显著不同。虽然与氮利用和类胡萝卜素生物合成相关的基因的密码子使用情况符合预期，这是基于红细菌一般的密码子使用情况，但果糖利用（fru）操纵子以及编码反应中心和光捕获蛋白的光合基因的密码子使用情况，对于特定氨基酸而言，显著偏离预期且彼此不同。fru操纵子与光合基因在密码子使用上的差异，可能反映了细胞在异养与光养条件下生长时，特定氨基酸的各种tRNA的不同比例。此外，还发现红细菌操纵子的第一个顺反子优先使用起始密码子GTG。
