5nwa

Crystal structure of the complex of Tdp1 with duplex DNA

spinqualitylabelsall models 5nwa, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5nwa is a 3 chain structure with sequence from Homo sapiens and Synthetic construct. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 3.2Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Disease TYDP1_HUMAN Defects in TDP1 are the cause of spinocerebellar ataxia autosomal recessive with axonal neuropathy (SCAN1) [MIM:607250. SCAN1 is an autosomal recessive cerebellar ataxia (ARCA) associated with peripheral axonal motor and sensory neuropathy, distal muscular atrophy, pes cavus and steppage gait as seen in Charcot-Marie-Tooth neuropathy. All affected individuals have normal intelligence. Function TYDP1_HUMAN DNA repair enzyme that can remove a variety of covalent adducts from DNA through hydrolysis of a 3'-phosphodiester bond, giving rise to DNA with a free 3' phosphate. Catalyzes the hydrolysis of dead-end complexes between DNA and the topoisomerase I active site tyrosine residue. Hydrolyzes 3'-phosphoglycolates on protruding 3' ends on DNA double-strand breaks due to DNA damage by radiation and free radicals. Acts on blunt-ended double-strand DNA breaks and on single-stranded DNA. Has low 3'exonuclease activity and can remove a single nucleoside from the 3'end of DNA and RNA molecules with 3'hydroxyl groups. Has no exonuclease activity towards DNA or RNA with a 3'phosphate. Publication Abstract from PubMed Tyrosyl-DNA phosphodiesterase (Tdp1) is a DNA 3'-end processing enzyme that repairs topoisomerase 1B-induced DNA damage. We use a new tool combining site-specific DNA-protein cross-linking with mass spectrometry to identify Tdp1 interactions with DNA. A conserved phenylalanine (F259) of Tdp1, required for efficient DNA processing in biochemical assays, cross-links to defined positions in DNA substrates. Crystal structures of Tdp1-DNA complexes capture the DNA repair machinery after 3'-end cleavage; these reveal how Tdp1 coordinates the 3'-phosphorylated product of nucleosidase activity and accommodates duplex DNA. A hydrophobic wedge splits the DNA ends, directing the scissile strand through a channel towards the active site. The F259 side-chain stacks against the -3 base pair, delimiting the junction of duplexed and melted DNA, and fixes the scissile strand in the channel. Our results explain why Tdp1 cleavage is non-processive and provide a molecular basis for DNA 3'-end processing by Tdp1. Structural basis for DNA 3'-end processing by human tyrosyl-DNA phosphodiesterase 1.,Flett FJ, Ruksenaite E, Armstrong LA, Bharati S, Carloni R, Morris ER, Mackay CL, Interthal H, Richardson JM Nat Commun. 2018 Jan 2;9(1):24. doi: 10.1038/s41467-017-02530-z. PMID:29295983 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Phosphodiesterase 3D structures

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