Loviny T, Norton P M, Hartley B S
Biochem J. 1985 Sep 15;230(3):579-85. doi: 10.1042/bj2300579.
The ribitol dehydrogenase gene was cloned from wild-type Klebsiella aerogenes and also from a transducing phage lambda prbt which expresses the rbt operon constitutively. The coding sequence for 249 amino acids is separated from the following D-ribulokinase gene by 31 base pairs containing three stop codons, one of which overlaps the ribosome binding site for D-ribulokinase. Three residues in the amino acid sequence differ from that predicted from the DNA sequence: Asp-212 for Asn-212 is probably a protein sequencing error, but -Ala-Val- for -Ser-Ser- at 146-147 appears to be a 'neutral mutation' that may have arisen during prolonged chemostat selection of a strain that superproduces the enzyme from which the protein sequence was determined.
核醇脱氢酶基因是从野生型产气克雷伯菌中克隆出来的,也从组成型表达rbt操纵子的转导噬菌体λprbt中克隆得到。由249个氨基酸组成的编码序列与后续的D - 核糖激酶基因被31个碱基对隔开,这31个碱基对包含三个终止密码子,其中一个与D - 核糖激酶的核糖体结合位点重叠。氨基酸序列中有三个残基与根据DNA序列预测的不同:Asp - 212变为Asn - 212可能是蛋白质测序错误,但146 - 147位的 - Ser - Ser - 变为 - Ala - Val - 似乎是一个“中性突变”,可能是在对超量产生该酶(用于确定蛋白质序列)的菌株进行长期恒化器选择过程中出现的。