PT  - JOURNAL ARTICLE
AU  - MICHAEL L. FREEDMAN
AU  - MARCO RABINOVITZ
TI  - Structure of the Large β-Chain Polyribosome of Rabbit Reticulocytes Rendered Isoleucine-Deficient by O-Methylthreonine
DP  - 1971 May 01
TA  - Molecular Pharmacology
PG  - 317--322
VI  - 7
IP  - 3
4099  - http://molpharm.aspetjournals.org/content/7/3/317.short
4100  - http://molpharm.aspetjournals.org/content/7/3/317.full
SO  - Mol Pharmacol1971 May 01; 7
AB  - 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.