title: The effect of modification of cytosines in Escherichia coli 16-S rRNA on reconstitution and function of 30-S ribosomes.
abstract: O-Methylhydroxylamine (methoxyamine) was used for selective modification of cytosine residues in Escherichia coli 16-S rRNA. It was shown that cytosines accessible for methoxyamination are randomly distributed along the 16-S rRNA chain. Preparations of methoxyaminated 16-S rRNA, containing 2--130 modified cytosines/chain, still retained the ability to bind 30-S proteins, but the physical assembly of reconstituted particles was incorrect. The protein compositions of the reconstituted and native particles did not differ qualitatively from each other. However, the amount of protein in reconstituted particles decreased with an increasing number of methoxyaminated cytosines in 16-S rRNA. The particles obtained sedimented slower than native 30-S subunits, lost their ability to associate with 50-S ribosomes and to bind native phage f2 RNA. In contrast, modification of 16-S rRNA did not affect binding of poly(U) by reconstituted particles.
mesh_terms: D003596:Cytosine / Q000031:analogs & derivatives*; D004926:Escherichia coli; D006898:Hydroxylamines; D010442:Peptide Chain Initiation, Translational; D011072:Poly U / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D012335:RNA, Ribosomal; D012367:RNA, Viral / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism / Q000648:ultrastructure; D013329:Structure-Activity Relationship
chemical_list: D006898:Hydroxylamines; D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012367:RNA, Viral; D011072:Poly U; D003596:Cytosine