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Location of translational initiation factor IF3 on the small ribosomal subunit

McCutcheon, John P. and Agrawal, Rajendra K. and Philips, Shibu M. and Grassucci, Robert A. and Gerchman, Sue Ellen and Clemons, William M., Jr. and Ramakrishnan, V. and Frank, Joachim (1999) Location of translational initiation factor IF3 on the small ribosomal subunit. Proceedings of the National Academy of Sciences of the United States of America, 96 (8). pp. 4301-4306. ISSN 0027-8424. PMCID PMC16327. doi:10.1073/pnas.96.8.4301.

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The location of translational initiation factor IF3 bound to the 30S subunit of the Thermus thermophilus ribosome has been determined by cryoelectron microscopy. Both the 30S⋅IF3 complex and control 30S subunit structures were determined to 27-Å resolution. The difference map calculated from the two reconstructions reveals three prominent lobes of positive density. The previously solved crystal structure of IF3 fits very well into two of these lobes, whereas the third lobe probably arises from conformational changes induced in the 30S subunit as a result of IF3 binding. Our placement of IF3 on the 30S subunit allows an understanding in structural terms of the biochemical functions of this initiation factor, namely its ability to dissociate 70S ribosomes into 30S and 50S subunits and the preferential selection of initiator tRNA by IF3 during initiation.

Item Type:Article
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URLURL TypeDescription CentralArticle
McCutcheon, John P.0000-0002-5489-6039
Clemons, William M., Jr.0000-0002-0021-889X
Additional Information:© 1999 National Academy of Sciences. Communicated by Peter B. Moore, Yale University, New Haven, CT (received for review January 7, 1999) We thank Amy B. Heagle for help with illustrations and Irene S. Gabashvili for help with some of the computation. This work was supported by National Institutes of Health grant R01GM 44973 (to V.R. and Stephen W. White) and R37GM 29169 and R01GM 55440 (to J.F.). The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.
Funding AgencyGrant Number
Subject Keywords:cryoelectron microscopy; ribosome
Issue or Number:8
PubMed Central ID:PMC16327
Record Number:CaltechAUTHORS:20181030-105013612
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Official Citation:Location of translational initiation factor IF3 on the small ribosomal subunit John P. McCutcheon, Rajendra K. Agrawal, Shibu M. Philips, Robert A. Grassucci, Sue Ellen Gerchman, William M. Clemons, V. Ramakrishnan, Joachim Frank Proceedings of the National Academy of Sciences Apr 1999, 96 (8) 4301-4306; DOI: 10.1073/pnas.96.8.4301
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:90500
Deposited By: George Porter
Deposited On:30 Oct 2018 20:32
Last Modified:16 Nov 2021 03:33

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