3lqv
From Proteopedia
Branch Recognition by SF3b14
Structural highlights
Function[PM14_HUMAN] Necessary for the splicing of pre-mRNA. Directly contacts the pre-mRNA branch site adenosine for the first catalytic step of splicing. Enters the spliceosome and associates with the pre-mRNA branch site as part of the 17S U2 or, in the case of the minor spliceosome, as part of the 18S U11/U12 snRNP complex, and thus may facilitate the interaction of these snRNP with the branch sites of U2 and U12 respectively. [SF3B1_HUMAN] Subunit of the splicing factor SF3B required for 'A' complex assembly formed by the stable binding of U2 snRNP to the branchpoint sequence (BPS) in pre-mRNA. Sequence independent binding of SF3A/SF3B complex upstream of the branch site is essential, it may anchor U2 snRNP to the pre-mRNA. May also be involved in the assembly of the 'E' complex. Belongs also to the minor U12-dependent spliceosome, which is involved in the splicing of rare class of nuclear pre-mRNA intron. Publication Abstract from PubMedHuman p14 (SF3b14), a component of the spliceosomal U2 snRNP, interacts directly with the pre-mRNA branch adenosine within the context of the bulged duplex formed between the pre-mRNA branch region and U2 snRNA. This association occurs early in spliceosome assembly and persists within the fully assembled spliceosome. Analysis of the crystal structure of a complex containing p14 and a peptide derived from p14-associated SF3b155 combined with the results of cross-linking studies has suggested that the branch nucleotide interacts with a pocket on a non-canonical RNA binding surface formed by the complex. Here we report a structural model of the p14 . bulged duplex interaction based on a combination of X-ray crystallography of an adenine p14/SF3b155 peptide complex, biochemical comparison of a panel of disulfide cross-linked protein-RNA complexes, and small-angle X-ray scattering (SAXS). These studies reveal specific recognition of the branch adenosine within the p14 pocket and establish the orientation of the bulged duplex RNA bound on the protein surface. The intimate association of one surface of the bulged duplex with the p14/SF3b155 peptide complex described by this model buries the branch nucleotide at the interface and suggests that p14 . duplex interaction must be disrupted before the first step of splicing. Structural model of the p14/SF3b155 . branch duplex complex.,Schellenberg MJ, Dul EL, MacMillan AM RNA. 2011 Jan;17(1):155-65. Epub 2010 Nov 9. PMID:21062891[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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