Localization of sites of photoaffinity labeling of the large subunit of Escherichia coli ribosomes by arylazide derivative of puromycin
Previous work showed that (TH)p-azidopuromycin photoaffinity labeled 70 S Escherichia coli ribosomes and that photoincorporation into 50 S subunit proteins was in the order L23 greater than L18/22 greater than L15. In the present work the authors report on immunoelectron microscopic studies of the complexes formed by p-azidopuromycin-modified 50 S subunits with antibodies to the N6,N6-dimethyladenosine moiety of the antibiotic. The p-azidopuromycin-modified 50 S subunits appear to be identical to unmodified control subunits in electron micrographs. Complexes of modified subunits with antibodies to the N6,N6-dimethyladenosine moiety of p-azidopuromycin were visualized in micrographs. Two regions of p-azidopuromycin photoincorporation were identified. The primary site, seen in about 75% of the complexes, is between the central protuberance and small projection, on the side away from the L7/L12 arm, in a region thought to contain the peptidyltransferase center. The secondary site, of unknown significance, is at the base of the subunit maximally distant from the arm. The data support the placement of proteins L23, L18/22, and L15 at or near the peptidyltransferase center at the primary site and suggest, in addition, that the secondary site includes a genuine area of puromycin affinity.
- OSTI ID:
- 6291643
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 18
- Country of Publication:
- United States
- Language:
- English
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TRACER TECHNIQUES
ANTIBODIES
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PUROMYCIN
ANTI-INFECTIVE AGENTS
ANTIBIOTICS
ANTINEOPLASTIC DRUGS
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DECOMPOSITION
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LABELLED COMPOUNDS
MICROORGANISMS
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ORGANIC NITROGEN COMPOUNDS
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550201* - Biochemistry- Tracer Techniques