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Protein Synthesis In Rabbit Reticulocytes: A Study Of The Mechanism Of Action Of The Protein Factor Rf That Reverses Protein Synthesis Inhibition In Heme-Deficient Reticulocyte Lysates, M. Grace, M. Bagchi, F. Ahmad, T. Yeager, C. Olson, I. Chakravarty, N. Nasrin, A. Banerjee, N. K. Gupta
Protein Synthesis In Rabbit Reticulocytes: A Study Of The Mechanism Of Action Of The Protein Factor Rf That Reverses Protein Synthesis Inhibition In Heme-Deficient Reticulocyte Lysates, M. Grace, M. Bagchi, F. Ahmad, T. Yeager, C. Olson, I. Chakravarty, N. Nasrin, A. Banerjee, N. K. Gupta
Chemistry Department: Faculty Publications
A eukaryotic initiation factor 2 (eIF-2)-ancillary protein factor Co-eIF-2 promotes displacement of GDP from eIF-2GDP and facilitates ternary complex (Met-tRNAf• eIF-2-GTP) formation in the presence of Mg2+. Heme-regulated protein synthesis inhibitor, HRI, phosphorylates the α-subunit of eIF-2 and thus inhibits ternary complex formation as Co-eIF•2 does not displace GDP from eIF-2α(P)•GDP. RF, a high molecular weight cell supernatant factor, reverses protein synthesis inhibition in heme-deficient reticulocyte lysates and also reverses HRI inhibition of ternary complex formation. RF contains Co-eIF•2 activity. In addition, an active RF preparation contains excess α-subunit of eIF-2 in the free and unphosphorylated …
Protein Synthesis In Rabbit Reticulocytes: Characteristics Of The Protein Factor Rf That Reverses Inhibition Of Protein Synthesis In Heme-Deficient Reticulocyte Lysates, Michael Grace, Robert O. Ralston, Ambica C. Banerjee, Naba K. Gupta
Protein Synthesis In Rabbit Reticulocytes: Characteristics Of The Protein Factor Rf That Reverses Inhibition Of Protein Synthesis In Heme-Deficient Reticulocyte Lysates, Michael Grace, Robert O. Ralston, Ambica C. Banerjee, Naba K. Gupta
Chemistry Department: Faculty Publications
During heme deficiency in reticulocyte lysates, the heme-regulated translational inhibitor of protein synthesis (HRI) is activated and shuts off protein synthesis. In partial reactions, HRI phosphorylates the Mr 38,000 subunit (α subunit) of eukaryotic initiation factor 2 (eIF-2), which forms a ternary complex, Met-tRNAf•eIF-2•GTP. The eIF-2α(P) thus formed is not recognized by two eIF-2 ancillary factors, Co-eIF-2B (which promotes the dissociation of the ternary complex at high Mg2+) and Co-eIF-2C (which reverses the inhibition of ternary complex formation), and thus, is presumably inactive in peptide chain initiation. A protein factor, designated RF, which reverses inhibition …