Cossart P, Groisman E A, Serre M C, Casadaban M J, Gicquel-Sanzey B
J Bacteriol. 1986 Aug;167(2):639-46. doi: 10.1128/jb.167.2.639-646.1986.
The complete nucleotide sequences of the Salmonella typhimurium LT2 and Shigella flexneri 2B crp genes were determined and compared with those of the Escherichia coli K-12 crp gene. The Shigella flexneri gene was almost like the E. coli crp gene, with only four silent base pair changes. The S. typhimurium and E. coli crp genes presented a higher degree of divergence in their nucleotide sequence with 77 changes, but the corresponding amino acid sequences presented only one amino acid difference. The nucleotide sequences of the crp genes diverged to the same extent as in the other genes, trp, ompA, metJ, and araC, which are structural or regulatory genes. An analysis of the amino acid divergence, however, revealed that the catabolite gene activator protein, the crp gene product, is the most conserved protein observed so far. Comparison of codon usage in S. typhimurium and E. coli for all genes sequenced in both organisms showed that their patterns were similar. Comparison of the regulatory regions of the S. typhimurium and E. coli crp genes showed that the most conserved sequences were those known to be essential for the expression of E. coli crp.
测定了鼠伤寒沙门氏菌LT2和福氏志贺氏菌2B的crp基因的完整核苷酸序列，并与大肠杆菌K-12的crp基因序列进行了比较。福氏志贺氏菌的基因几乎与大肠杆菌的crp基因相同，只有四个沉默碱基对变化。鼠伤寒沙门氏菌和大肠杆菌的crp基因在核苷酸序列上有更高程度的差异，有77个变化，但相应的氨基酸序列只有一个氨基酸差异。crp基因的核苷酸序列与其他基因（trp、ompA、metJ和araC，这些都是结构或调节基因）的差异程度相同。然而，对氨基酸差异的分析表明，分解代谢物基因激活蛋白（crp基因产物）是迄今为止观察到的最保守的蛋白质。对鼠伤寒沙门氏菌和大肠杆菌中所有已测序基因的密码子使用情况进行比较，结果表明它们的模式相似。对鼠伤寒沙门氏菌和大肠杆菌crp基因调控区的比较表明，最保守的序列是那些已知对大肠杆菌crp表达至关重要的序列。
