6n19
Crystal structure of Tdp1 catalytic domain in complex with compound XZ578
Structural highlights
DiseaseTYDP1_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.[1] [2] [3] [4] [5] FunctionTYDP1_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.[6] [7] [8] [9] [10] Publication Abstract from PubMedTyrosyl DNA-phosphodiesterase I (TDP1) repairs type IB topoisomerase (TOP1) cleavage complexes generated by TOP1 inhibitors commonly used as anticancer agents. TDP1 also removes DNA 3' end blocking lesions generated by chain-terminating nucleosides and alkylating agents, and base oxidation both in the nuclear and mitochondrial genomes. Combination therapy with TDP1 inhibitors is proposed to synergize with topoisomerase targeting drugs to enhance selectivity against cancer cells exhibiting deficiencies in parallel DNA repair pathways. A crystallographic fragment screening campaign against the catalytic domain of TDP1 was conducted to identify new lead compounds. Crystal structures revealed two fragments that bind to the TDP1 active site and exhibit inhibitory activity against TDP1. These fragments occupy a similar position in the TDP1 active site as seen in prior crystal structures of TDP1 with bound vanadate, a transition state mimic. Using structural insights into fragment binding, several fragment derivatives have been prepared and evaluated in biochemical assays. These results demonstrate that fragment-based methods can be a highly feasible approach toward the discovery of small-molecule chemical scaffolds to target TDP1, and for the first time, we provide co-crystal structures of small molecule inhibitors bound to TDP1, which could serve for the rational development of medicinal TDP1 inhibitors. Identification of a ligand binding hot spot and structural motifs replicating aspects of tyrosyl-DNA phosphodiesterase I (TDP1) phosphoryl recognition by crystallographic fragment cocktail screening.,Lountos GT, Zhao XZ, Kiselev E, Tropea JE, Needle D, Pommier Y, Burke TR, Waugh DS Nucleic Acids Res. 2019 Jun 14. pii: 5519170. doi: 10.1093/nar/gkz515. PMID:31199869[11] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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