2jp7
From Proteopedia
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NMR structure of the Mex67 UBA domain
Overview
The ubiquitin-associated (UBA) domain of the mRNA nuclear export receptor, Mex67 helps in coordinating transcription elongation and nuclear export by, interacting both with ubiquitin conjugates and specific targets, such as, Hpr1, a component of the THO complex. Here, we analyzed substrate, specificity and ubiquitin selectivity of the Mex67 UBA domain. UBA-Mex67, is formed by three helices arranged in a classical UBA fold plus a fourth, helix, H4. Deletion or mutation of helix H4 strengthens the interaction, between UBA-Mex67 and ubiquitin, but it decreases its affinity for Hpr1., Interaction with Hpr1 is required for Mex67 UBA domain to bind, polyubiquitin, possibly by inducing an H4-dependent conformational change., In vivo, deletion of helix H4 reduces cotranscriptional recruitment of, Mex67 on activated genes, and it also shows an mRNA export defect. Based, on these results, we propose that H4 functions as a molecular switch that, coordinates the interaction of Mex67 with ubiquitin bound to specific, substrates, defines the selectivity of the Mex67 UBA domain for, polyubiquitin, and prevents its binding to nonspecific substrates.
About this Structure
2JP7 is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Coordination of Hpr1 and ubiquitin binding by the UBA domain of the mRNA export factor Mex67., Hobeika M, Brockmann C, Iglesias N, Gwizdek C, Neuhaus D, Stutz F, Stewart M, Divita G, Dargemont C, Mol Biol Cell. 2007 Jul;18(7):2561-8. Epub 2007 May 2. PMID:17475778
Page seeded by OCA on Wed Jan 23 14:06:55 2008
