Two homologous EF-G proteins from Pseudomonas aeruginosa exhibit distinct functions.
Two homologous EF-G proteins from Pseudomonas aeruginosa exhibit distinct functions.
复制标题
DOI：
10.1371/journal.pone.0080252
复制
发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Bullard JM
中科院分区：
文献类型：
--
作者：
Palmer SO;Rangel EY;Hu Y;Tran AT;Bullard JM
Please try later.
Genes encoding two proteins corresponding to elongation factor G (EF-G) were cloned from Pseudomonas aeruginosa. The proteins encoded by these genes are both members of the EFG I subfamily. The gene encoding one of the forms of EF-G is located in the str operon and the resulting protein is referred to as EF-G1A while the gene encoding the other form of EF-G is located in another part of the genome and the resulting protein is referred to as EF-G1B. These proteins were expressed and purified to 98% homogeneity. Sequence analysis indicated the two proteins are 90/84% similar/identical. In other organisms containing multiple forms of EF-G a lower degree of similarity is seen. When assayed in a poly(U)-directed poly-phenylalanine translation system, EF-G1B was 75-fold more active than EF-G1A. EF-G1A pre-incubate with ribosomes in the presence of the ribosome recycling factor (RRF) decreased polymerization of poly-phenylalanine upon addition of EF-G1B in poly(U)-directed translation suggesting a role for EF-G1A in uncoupling of the ribosome into its constituent subunits. Both forms of P. aeruginosa EF-G were active in ribosome dependent GTPase activity. The kinetic parameters (K M) for the interaction of EF-G1A and EF-G1B with GTP were 85 and 70 μM, respectively. However, EF-G1B exhibited a 5-fold greater turnover number (observed k cat) for the hydrolysis of GTP than EF-G1A; 0.2 s-1 vs. 0.04 s-1. These values resulted in specificity constants (k cat obs/K M) for EF-G1A and EF-G1B of 0.5 x 103 s-1 M-1 and 3.0 x 103 s-1 M-1, respectively. The antibiotic fusidic acid (FA) completely inhibited poly(U)-dependent protein synthesis containing P. aeruginosa EF-G1B, but the same protein synthesis system containing EF-G1A was not affected. Likewise, the activity of EF-G1B in ribosome dependent GTPase assays was completely inhibited by FA, while the activity of EF-G1A was not affected.
登录
查看更多内容
影响因子：
5.4
作者：
Chen, Yang;Koripella, Ravi Kiran;Selmer, Maria
通讯作者：
Selmer, Maria
DOI：
10.1016/0006-291x(69)90934-6
发表时间：
1969-01-01
影响因子：
3.1
作者：
BODLEY, JW;ZIEVE, FJ;ZIEVE, ST
通讯作者：
ZIEVE, ST
影响因子：
10.7
作者：
Atkinson, Gemma C.;Baldauf, Sandra L.
通讯作者：
Baldauf, Sandra L.
影响因子：
11.4
作者：
CZWORKOWSKI, J;WANG, J;MOORE, PB
通讯作者：
MOORE, PB
影响因子：
3.5
作者：
ALAKHOV, YB;DOVGAS, NV;OVCHINNIKOV, YA
通讯作者：
OVCHINNIKOV, YA