Maguire B A, Wild D G
Department of Biochemistry, University of Oxford, United Kingdom.
J Bacteriol. 1997 Apr;179(8):2486-93. doi: 10.1128/jb.179.8.2486-2493.1997.
The rpmBG operon of Escherichia coli codes for ribosomal proteins L28 and L33. Two strains with mutations in the operon are AM81, whose ribosomes lack protein L28, and AM90, whose ribosomes are without protein L33. Neither strain showed major defects in ribosome assembly. However, when the mutations were transferred to other strains of E. coli, ribosome synthesis was greatly perturbed and precursor ribonucleoproteins accumulated. In the new backgrounds, the mutation in rpmB was complemented by synthesis of protein L28 from a plasmid; the rpmG mutation was not complemented by protein L33 because synthesis of protein L28 from the upstream rpmB gene was also greatly reduced. The results suggest that protein L33, in contrast to protein L28, has at best a minor role in ribosome assembly and function.
大肠杆菌的rpmBG操纵子编码核糖体蛋白L28和L33。该操纵子发生突变的两个菌株分别是AM81，其核糖体缺乏蛋白L28；以及AM90，其核糖体没有蛋白L33。这两个菌株在核糖体组装方面均未表现出重大缺陷。然而，当这些突变转移到其他大肠杆菌菌株时，核糖体合成受到极大干扰，前体核糖核蛋白积累。在新的背景下，rpmB中的突变可通过从质粒合成蛋白L28来互补；rpmG突变不能被蛋白L33互补，因为来自上游rpmB基因的蛋白L28合成也大幅减少。结果表明，与蛋白L28相比，蛋白L33在核糖体组装和功能中至多起次要作用。
