1q32
From Proteopedia
Crystal Structure Analysis of the Yeast Tyrosyl-DNA Phosphodiesterase
Structural highlights
Function[TYDP1_YEAST] 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. Cleaves also 5' phosphotyrosyl adducts resulting from dead-end complexes between DNA and the active site tyrosine of topoisomerase II. Contributes to DNA repair after radiation damage. Acts on blunt-ended double-strand DNA breaks and on single-stranded DNA. May have low 3'exonuclease activity and may be able to 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 (By similarity).[1] [2] 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 PubMedTyrosyl-DNA phosphodiesterase 1 (Tdp1) catalyzes the resolution of 3' and 5' phospho-DNA adducts. A defective mutant, associated with the recessive neurodegenerative disease SCAN1, accumulates Tdp1-DNA complexes in vitro. To assess the conservation of enzyme architecture, a 2.0 A crystal structure of yeast Tdp1 was determined that is very similar to human Tdp1. Poorly conserved regions of primary structure are peripheral to an essentially identical catalytic core. Enzyme mechanism was also conserved, because the yeast SCAN1 mutant (H(432)R) enhanced cell sensitivity to the DNA topoisomerase I (Top1) poison camptothecin. A more severe Top1-dependent lethality of Tdp1H(432)N was drug-independent, coinciding with increased covalent Top1-DNA and Tdp1-DNA complex formation in vivo. However, both H(432) mutants were recessive to wild-type Tdp1. Thus, yeast H(432) acts in the general acid/base catalytic mechanism of Tdp1 to resolve 3' phosphotyrosyl and 3' phosphoamide linkages. However, the distinct pattern of mutant Tdp1 activity evident in yeast cells, suggests a more severe defect in Tdp1H(432)N-catalyzed resolution of 3' phospho-adducts. Mutation of a conserved active site residue converts tyrosyl-DNA phosphodiesterase I into a DNA topoisomerase I-dependent poison.,He X, van Waardenburg RC, Babaoglu K, Price AC, Nitiss KC, Nitiss JL, Bjornsti MA, White SW J Mol Biol. 2007 Sep 28;372(4):1070-81. Epub 2007 Aug 2. PMID:17707402[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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