Download MendeleyA 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, T.C., Godin, K.S., Edwards, T.E., Sigurdsson, S.T., Rozenkrants, N., Nagel, R.J., Ares, M., Varani, G.(2004) EMBO J 23: 2468-2477
- PubMed: 15192703
- DOI: https://doi.org/10.1038/sj.emboj.7600260
- Primary Citation of Related Structures:
1T4N, 1T4O - PubMed Abstract:
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.
Organizational Affiliation:
Institut de Biochimie et de Biophysique Moléculaire et Cellulaire (CNRS-UMR 8619), Université Paris-Sud, Orsay, France.
