2aar
From Proteopedia
Structure of trigger factor binding domain in biologically homologous complex with eubacterial ribosome.
Structural highlights
Function[TIG_DEIRA] Involved in protein export. Acts as a chaperone by maintaining the newly synthesized protein in an open conformation. Functions as a peptidyl-prolyl cis-trans isomerase (By similarity). Probably changes conformation upon binding to the ribosome (maybe in particular due to interaction with L24, PubMed:16271892), exposing a hydrophobic crevice that is probably important for its chaperone activity (PubMed:16091460 and PubMed:16271892).[HAMAP-Rule:MF_00303] [RL29_DEIRA] Binds the 23S rRNA. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit.[HAMAP-Rule:MF_00374] [RL23_DEIRA] One of the early assembly protein (By similarity) it binds 23S rRNA. One of the proteins that surrounds the polypeptide exit tunnel on the outside of the subunit. Forms the main docking site for trigger factor binding to the ribosome (PubMed:16091460 and PubMed:16271892).[HAMAP-Rule:MF_01369] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedTrigger factor (TF), the first chaperone in eubacteria to encounter the emerging nascent chain, binds to the large ribosomal subunit in the vicinity of the protein exit tunnel opening and forms a sheltered folding space. Here, we present the 3.5-A crystal structure of the physiological complex of the large ribosomal subunit from the eubacterium Deinococcus radiodurans with the N-terminal domain of TF (TFa) from the same organism. For anchoring, TFa exploits a small ribosomal surface area in the vicinity of proteins L23 and L29, by using its "signature motif" as well as additional structural elements. The molecular details of TFa interactions reveal that L23 is essential for the association of TF with the ribosome and may serve as a channel of communication with the nascent chain progressing in the tunnel. L29 appears to induce a conformational change in TFa, which results in the exposure of TFa hydrophobic patches to the opening of the ribosomal exit tunnel, thus increasing its affinity for hydrophobic segments of the emerging nascent polypeptide. This observation implies that, in addition to creating a protected folding space for the emerging nascent chain, TF association with the ribosome prevents aggregation by providing a competing hydrophobic environment and may be critical for attaining the functional conformation necessary for chaperone activity. Structure of trigger factor binding domain in biologically homologous complex with eubacterial ribosome reveals its chaperone action.,Baram D, Pyetan E, Sittner A, Auerbach-Nevo T, Bashan A, Yonath A Proc Natl Acad Sci U S A. 2005 Aug 23;102(34):12017-22. Epub 2005 Aug 9. PMID:16091460[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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