title: Valyl-tRNA synthetase modification-dependent restriction of bacteriophage T4.
abstract: A strain of Escherichia coli, CP 790302, severely restricts the growth of wild-type bacteriophage T4. In broth culture, most infections of single cells are abortive, although a few infected cells exhibit reduced burst sizes. In contrast, bacteriophage T4 mutants impaired in the ability to modify valyl-tRNA synthetase develop normally on this strain. Biochemical evidence indicates that the phage-modified valyl-tRNA synthetase in CP 790302 is different from that previously described. Although the enzyme is able to support normal protein synthesis, a disproportionate amount of phage structural protein (serum blocking power) fails to mature into particles of the appropriate density. The results with host strain CP 790302 are consistent with either a gratuitous inhibition of phage assembly by faulty modification or abrogation of an unknown role that valyl-tRNA synthetase might normally play in viral assembly.
mesh_terms: D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D004926:Escherichia coli / Q000201:enzymology*; D006358:Hot Temperature; D046911:Macromolecular Substances; D012346:RNA, Transfer, Amino Acyl / Q000378:metabolism; D013604:T-Phages / Q000254:growth & development*; D014637:Valine-tRNA Ligase / Q000302:isolation & purification / Q000378:metabolism*; D014764:Viral Proteins / Q000096:biosynthesis; D014779:Virus Replication
chemical_list: D046911:Macromolecular Substances; D012346:RNA, Transfer, Amino Acyl; D014764:Viral Proteins; D000604:Amino Acyl-tRNA Synthetases; D014637:Valine-tRNA Ligase