Mutation analysis of the role in ribosomal translocation for loops of domain IV of the elongation factor G

被引:1
|
作者
Kolesnikov, AV [1 ]
Gudkov, AT [1 ]
机构
[1] Russian Acad Sci, Inst Prot Res, Pushchino 142290, Moscow Region, Russia
关键词
elongation factor G; mutagenesis; translation; structure; function; Thermus thermophilus;
D O I
10.1023/A:1025151830588
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Seven variants of Thermus thermophilus elongation factor G (EF-G) with mutations in loops of domain IV were constructed by PCR. Point mutations AT504 --> Thr, Pro554 --> Thr, or Ile534 --> Asp did not affect the GTPase and translocational activities of EF-G. Similar results were obtained for mutants with tetra- or hexapeptide inserts in two loops located at the tip and two loops at the base of domain IV. Insertion of tetrapeptide Gly-Ser-Gly-Thr into loop 501-504 at the tip of domain IV dramatically reduced the activity of EF-G in poly(U)-directed polyphenylalanine synthesis on ribosomes, and halved its translocational activity. The intact conformation of loop Thr-501-Gly-Gly-Arg504 was assumed to be essential for sterically perfect, efficient interaction of EF-G with the ribosome. The structural and biochemical data on the 30S subunit and EF-G were analyzed to specify the position of EF-G relative to the 30S and 50S ribosomal subunits.
引用
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页码:611 / 616
页数:6
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