3o2s

Crystal structure of the human symplekin-Ssu72 complex

spinqualitylabelsall models 3o2s, resolution 2.50Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3o2s is a 2 chain structure with sequence from Human. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: PO4 Related: 3o2q, 3o2t Gene: SYMPK, SPK (HUMAN), SSU72, HSPC182, PNAS-120 (HUMAN) Activity: Phosphoprotein phosphatase, with EC number 3.1.3.16 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [SYMPK_HUMAN] Scaffold protein that functions as a component of a multimolecular complex involved in histone mRNA 3'-end processing. Specific component of the tight junction (TJ) plaque, but might not be an exclusively junctional component. May have a house-keeping rule. Is involved in pre-mRNA polyadenylation. Enhances SSU72 phosphatase activity. [SSU72_HUMAN] Protein phosphatase that catalyzes the dephosphorylation of the C-terminal domain of RNA polymerase II. Plays a role in RNA processing and termination. Plays a role in pre-mRNA polyadenylation via its interaction with SYMPK. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed Symplekin (Pta1 in yeast) is a scaffold in the large protein complex that is required for 3'-end cleavage and polyadenylation of eukaryotic messenger RNA precursors (pre-mRNAs); it also participates in transcription initiation and termination by RNA polymerase II (Pol II). Symplekin mediates interactions between many different proteins in this machinery, although the molecular basis for its function is not known. Here we report the crystal structure at 2.4 A resolution of the amino-terminal domain (residues 30-340) of human symplekin in a ternary complex with the Pol II carboxy-terminal domain (CTD) Ser 5 phosphatase Ssu72 (refs 7, 10-17) and a CTD Ser 5 phosphopeptide. The N-terminal domain of symplekin has the ARM or HEAT fold, with seven pairs of antiparallel alpha-helices arranged in the shape of an arc. The structure of Ssu72 has some similarity to that of low-molecular-mass phosphotyrosine protein phosphatase, although Ssu72 has a unique active-site landscape as well as extra structural features at the C terminus that are important for interaction with symplekin. Ssu72 is bound to the concave face of symplekin, and engineered mutations in this interface can abolish interactions between the two proteins. The CTD peptide is bound in the active site of Ssu72, with the pSer 5-Pro 6 peptide bond in the cis configuration, which contrasts with all other known CTD peptide conformations. Although the active site of Ssu72 is about 25 A from the interface with symplekin, we found that the symplekin N-terminal domain stimulates Ssu72 CTD phosphatase activity in vitro. Furthermore, the N-terminal domain of symplekin inhibits polyadenylation in vitro, but only when coupled to transcription. Because catalytically active Ssu72 overcomes this inhibition, our results show a role for mammalian Ssu72 in transcription-coupled pre-mRNA 3'-end processing. Crystal structure of the human symplekin-Ssu72-CTD phosphopeptide complex.,Xiang K, Nagaike T, Xiang S, Kilic T, Beh MM, Manley JL, Tong L Nature. 2010 Sep 22. PMID:20861839 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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