Barroga C F, Zhang H, Wajih N, Bouyer J H, Hermodson M A
Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907-1153, USA.
Protein Sci. 1996 Jun;5(6):1093-9. doi: 10.1002/pro.5560050611.
The nucleotide-binding component of the high-affinity ribose transport system of Escherichia coli, RbsA, was overproduced from a T7-7 expression vector, and the protein was purified. Biochemical analyses of the purified protein indicated that the ATP analogues, 5'-FSBA and 8-azido ATP, covalently labeled the protein, a reaction that was inhibited by ATP, but not by GTP or CTP. The pure protein exhibited low-level ATPase activity with a K(m) of about 140 microM. Analyses of bacterial strains carrying chromosomal deletions of rbsA and other rbs genes suggested that RbsA is important for the chemotaxis function, a surprising result that was not anticipated from previous studies. However, an inconsistency between the several results from deletion strains raises questions regarding the interpretations of the in vivo data.
大肠杆菌高亲和力核糖转运系统的核苷酸结合成分RbsA，通过T7-7表达载体过量表达，并对该蛋白质进行了纯化。对纯化蛋白质的生化分析表明，ATP类似物5'-FSBA和8-叠氮基ATP与该蛋白质发生共价标记，该反应受到ATP抑制，但不受GTP或CTP抑制。纯蛋白质表现出低水平的ATP酶活性，K(m)约为140微摩尔。对携带rbsA和其他rbs基因染色体缺失的细菌菌株的分析表明，RbsA对趋化功能很重要，这一惊人结果是先前研究未曾预料到的。然而，缺失菌株的几个结果之间的不一致引发了对体内数据解释的质疑。
