4v6s
From Proteopedia
Structural characterization of mRNA-tRNA translocation intermediates (class 3 of the six classes)
Structural highlights
FunctionRL4_ECOLI One of the primary rRNA binding proteins, this protein initially binds near the 5'-end of the 23S rRNA. It is important during the early stages of 50S assembly. It makes multiple contacts with different domains of the 23S rRNA in the assembled 50S subunit and ribosome.[1] Protein L4 is a both a transcriptional repressor and a translational repressor protein; these two functions are independent of each other. It regulates transcription of the S10 operon (to which L4 belongs) by causing premature termination of transcription within the S10 leader; termination absolutely requires the NusA protein. L4 controls the translation of the S10 operon by binding to its mRNA. The regions of L4 that control regulation (residues 131-210) are different from those required for ribosome assembly (residues 89-103).[2] Forms part of the polypeptide exit tunnel.[3] Can regulate expression from Citrobacter freundii, Haemophilus influenzae, Morganella morganii, Salmonella typhimurium, Serratia marcescens, Vibrio cholerae and Yersinia enterocolitica (but not Pseudomonas aeruginosa) S10 leaders in vitro.[4] Publication Abstract from PubMedCryo-EM analysis of a wild-type Escherichia coli pretranslocational sample has revealed the presence of previously unseen intermediate substates of the bacterial ribosome during the first phase of translocation, characterized by intermediate intersubunit rotations, L1 stalk positions, and tRNA configurations. Furthermore, we describe the domain rearrangements in quantitative terms, which has allowed us to characterize the processivity and coordination of the conformational reorganization of the ribosome, along with the associated changes in tRNA ribosome-binding configuration. The results are consistent with the view of the ribosome as a molecular machine employing Brownian motion to reach a functionally productive state via a series of substates with incremental changes in conformation. Structural characterization of mRNA-tRNA translocation intermediates.,Agirrezabala X, Liao HY, Schreiner E, Fu J, Ortiz-Meoz RF, Schulten K, Green R, Frank J Proc Natl Acad Sci U S A. 2012 Mar 30. PMID:22467828[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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Categories: Escherichia coli | Large Structures | Agirrezabala X | Frank J | Fu J | Green R | Liao H | Ortiz-Meoz RF | Schreiner E | Schulten K
