1t4o
From Proteopedia
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Crystal structure of rnt1p dsRBD
Overview
Rnt1 endoribonuclease, the yeast homolog of RNAse III, plays an important, role in the maturation of a diverse set of RNAs. The enzymatic activity, requires a conserved catalytic domain, while RNA binding requires the, double-stranded RNA-binding domain (dsRBD) at the C-terminus of the, protein. While bacterial RNAse III enzymes cleave double-stranded RNA, Rnt1p specifically cleaves RNAs that possess short irregular stem-loops, containing 12-14 base pairs interrupted by internal loops and bulges and, capped by conserved AGNN tetraloops. Consistent with this substrate, specificity, the isolated Rnt1p dsRBD and the 30-40 amino acids that, follow bind to AGNN-containing stem-loops preferentially in vitro. In, order to understand how Rnt1p recognizes its cognate processing sites, we, have defined its minimal RNA-binding domain and determined its structure, by solution NMR spectroscopy and X-ray crystallography. We observe a new, carboxy-terminal helix following a canonical dsRBD structure. Removal of, this helix reduces binding to Rnt1p substrates. The results suggest that, this helix allows the Rnt1p dsRBD to bind to short RNA stem-loops by, modulating the conformation of helix alpha1, a key RNA-recognition element, of the dsRBD.
About this Structure
1T4O is a Single protein structure of sequence from Saccharomyces cerevisiae. Active as Ribonuclease III, with EC number 3.1.26.3 Full crystallographic information is available from OCA.
Reference
A new alpha-helical extension promotes RNA binding by the dsRBD of Rnt1p RNAse III., Leulliot N, Quevillon-Cheruel S, Graille M, van Tilbeurgh H, Leeper TC, Godin KS, Edwards TE, Sigurdsson ST, Rozenkrants N, Nagel RJ, Ares M, Varani G, EMBO J. 2004 Jul 7;23(13):2468-77. Epub 2004 Jun 10. PMID:15192703
Page seeded by OCA on Wed Nov 21 02:59:23 2007
