title: Structure of the mRNA splicing complex component Cwc2: insights into RNA recognition.
abstract: The Prp19-associated complex [NTC (nineteen complex)] plays a crucial role in intron removal during premature mRNA splicing in eukaryotes. Only one component of the NTC, Cwc2, is capable of binding RNA. In the present study we report the 1.9 Å (1 Å=0.1 nm) X-ray structure of the Cwc2 core domain, which is both necessary and sufficient for RNA binding. The Cwc2 core domain contains two sub-domains, a CCCH-type ZnF (zinc finger) and a RRM (RNA recognition motif). Unexpectedly, the ZnF domain and the RRM form a single folding unit, glued together by extensive hydrophobic interactions and hydrogen bonds. Structure-guided mutational analysis revealed that the intervening loop [known as the RB loop (RNA-binding loop)] between ZnF and RRM plays an essential role in RNA binding. In addition, a number of highly conserved positively charged residues on the β-strands of RRM make an important contribution to RNA binding. Intriguingly, these residues and a portion of the RB loop constitute an extended basic surface strip that encircles Cwc2 halfway. The present study serves as a framework for understanding the regulatory function of the NTC in RNA splicing.
authors.affiliation: Center of Structural Biology, Tsinghua University, Beijing 100084, China.
authors.forename: Peilong
authors.initials: P
authors.lastname: Lu
authors.forename: Guifeng
authors.initials: G
authors.lastname: Lu
authors.forename: Chuangye
authors.initials: C
authors.lastname: Yan
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.forename: Wenqi
authors.initials: W
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Yin
mesh_terms: D020816:Amino Acid Motifs; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins / Q000737:chemistry*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D017381:Spliceosomes / Q000737:chemistry*; D016335:Zinc Fingers
chemical_list: C543031:Cwc2 protein, S cerevisiae; C079877:PRP19 protein, S cerevisiae; D000072260:RNA Splicing Factors; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins