Localization of spermine binding sites in 23S rRNA by photoaffinity labeling: parsing the spermine contribution to ribosomal 50S subunit functions.

ABSTRACT: Polyamine binding to 23S rRNA was investigated, using a photoaffinity labeling approach. This was based on the covalent binding of a photoreactive analog of spermine, N1-azidobenzamidino (ABA)-spermine, to Escherichia coli ribosomes or naked 23S rRNA under mild irradiation conditions. The cross-linking sites of ABA-spermine in 23S rRNA were determined by RNase H digestion and primer-extension analysis. Domains I, II, IV and V in naked 23S rRNA were identified as discrete regions of preferred cross-linking. When 50S ribosomal subunits were targeted, the interaction of the photoprobe with the above 23S rRNA domains was elevated, except for helix H38 in domain II whose susceptibility to cross-linking was greatly reduced. In addition, cross-linking sites were identified in domains III and VI.

SUBMITTER: Xaplanteri MA 

PROVIDER: S-EPMC1129027 | biostudies-literature | 2005

REPOSITORIES: biostudies-literature