3p6y
CF Im25-CF Im68-UGUAA complex
Structural highlights
FunctionCPSF5_HUMAN Component of the cleavage factor Im (CFIm) complex that plays a key role in pre-mRNA 3'-processing. Involved in association with CPSF6 or CPSF7 in pre-MRNA 3'-end poly(A) site cleavage and poly(A) addition. NUDT21/CPSF5 binds to cleavage and polyadenylation RNA substrates. The homodimer mediates simultaneous sequence-specific recognition of two 5'-UGUA-3' elements within the pre-mRNA. Binds to, but does not hydrolyze mono- and di-adenosine nucleotides. May have a role in mRNA export.[1] [2] [3] [4] [5] [6] Publication Abstract from PubMedThe cleavage factor I(m) (CF I(m)), consists of a 25 kDa subunit (CF I(m)25) and one of three larger subunits (CF I(m)59, CF I(m)68, CF I(m)72), and is an essential protein complex for pre-mRNA 3'-end cleavage and polyadenylation. It recognizes the upstream sequence of the poly(A) site in a sequence-dependent manner. Here we report the crystal structure of human CF I(m), comprising CF I(m)25 and the RNA recognition motif domain of CF I(m)68 (CF I(m)68RRM), and the crystal structure of the CF I(m)-RNA complex. These structures show that two CF I(m)68RRM molecules bind to the CF I(m)25 dimer via a novel RRM-protein interaction mode forming a heterotetramer. The RNA-bound structure shows that two UGUAA RNA sequences, with anti-parallel orientation, bind to one CF I(m)25-CF I(m)68RRM heterotetramer, providing structural basis for the mechanism by which CF I(m) binds two UGUAA elements within one molecule of pre-mRNA simultaneously. Point mutation and kinetic analyses demonstrate that CF I(m)68RRM can bind the immediately flanking upstream region of the UGUAA element, and CF I(m)68RRM binding significantly increases the RNA-binding affinity of the complex, suggesting that CF I(m)68 makes an essential contribution to pre-mRNA binding. Structural basis of pre-mRNA recognition by the human cleavage factor Im complex.,Li H, Tong S, Li X, Shi H, Ying Z, Gao Y, Ge H, Niu L, Teng M Cell Res. 2011 Jul;21(7):1039-51. doi: 10.1038/cr.2011.67. Epub 2011 Apr 12. PMID:21483454[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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