5fj4
From Proteopedia
Structure of the standard kink turn HmKt-7 as stem loop bound with U1A and L7Ae proteins
Structural highlights
Function[SNRPA_HUMAN] Binds stem loop II of U1 snRNA. It is the first snRNP to interact with pre-mRNA. This interaction is required for the subsequent binding of U2 snRNP and the U4/U6/U5 tri-snRNP. In a snRNP-free form (SF-A) may be involved in coupled pre-mRNA splicing and polyadenylation process. Binds preferentially to the 5'-UGCAC-3' motif in vitro.[1] [RL7A_ARCFU] Multifunctional RNA-binding protein that recognizes the K-turn motif in ribosomal RNA, box H/ACA and box C/D sRNAs.[2] Publication Abstract from PubMedk-turns are commonly-occurring motifs that introduce sharp kinks into duplex RNA, thereby facilitating tertiary contacts. Both the folding and conformation of k-turns are determined by their local sequence. k-turns fall into two conformational classes, called N3 and N1, that differ in the pattern of hydrogen bonding in the core. We show here that this is determined by the basepair adjacent to the critical G*A pairs. We determined crystal structures of a series of Kt-7 variants in which this 3b,3n position has been systematically varied, showing that this leads to a switch in the conformation. We have previously shown that the 3b,3n position also determines the folding characteristics of the k-turn, i.e. whether or not the k-turn can fold in the presence of metal ions alone. We have analyzed the distribution of 3b,3n sequences from four classes of k-turns from ribosomes, riboswitches and U4 snRNA, finding a strong conservation of properties for a given k-turn type. We thus demonstrate a strong association between biological function, 3b,3n sequence and k-turn folding and conformation. This has strong predictive power, and can be applied to the modeling of large RNA architectures. A critical base pair in k-turns determines the conformational class adopted, and correlates with biological function.,Huang L, Wang J, Lilley DM Nucleic Acids Res. 2016 Mar 25. pii: gkw201. PMID:27016741[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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