Abstract
Incubation of rabbit reticulocytes with L-O-methylthreonine, an analogue of L-isoleucine, results in the formation of a unique, large β-chain polyribosome containing approximately 12 ribosomes. Two possible mechanisms for the formation of this polyribosome are considered: (a) the polyribosome may be formed by maximal packing of ribosomes on a β-chain mRNA strand proximal to the limiting isoleucine codon, on (b) there may be dimerization of lighter polyribosomes by an interaction of the blocked nascent β-chains. The nascent chains were removed from the ribosomes in intact cells by incubation with puromycin, and from the isolated ribosome-polyribosome component by incubation with Pronase. In both cases the large polyribosome remained after the nascent chains were removed, suggesting that it is formed by maximal packing of ribosomes on a β-chain mRNA strand.
- Copyright © 1971 by Academic Press, Inc.
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