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| - | [[Image:1qzq.gif|left|200px]] | + | {{Seed}} |
| | + | [[Image:1qzq.png|left|200px]] |
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| | {{STRUCTURE_1qzq| PDB=1qzq | SCENE= }} | | {{STRUCTURE_1qzq| PDB=1qzq | SCENE= }} |
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| - | '''human Tyrosyl DNA phosphodiesterase'''
| + | ===human Tyrosyl DNA phosphodiesterase=== |
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| - | ==Overview==
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| - | Tyrosyl-DNA phosphodiesterase I (Tdp1) is involved in the repair of DNA lesions created by topoisomerase I in vivo. Tdp1 is a member of the phospholipase D (PLD) superfamily of enzymes and hydrolyzes 3'-phosphotyrosyl bonds to generate 3'-phosphate DNA and free tyrosine in vitro. Here, we use synthetic 3'-(4-nitro)phenyl, 3'-(4-methyl)phenyl, and 3'-tyrosine phosphate oligonucleotides to study human Tdp1. Kinetic analysis of human Tdp1 (hTdp1) shows that the enzyme has nanomolar affinity for all three substrates and the overall in vitro reaction is diffusion-limited. Analysis of active-site mutants using these modified substrates demonstrates that hTdp1 uses an acid/base catalytic mechanism. The results show that histidine 493 serves as the general acid during the initial transesterification, in agreement with hypotheses based on previous crystal structure models. The results also argue that lysine 495 and asparagine 516 participate in the general acid reaction, and the analysis of crystal structures suggests that these residues may function in a proton relay. Together with previous crystal structure data, the new functional data provide a mechanistic understanding of the conserved histidine, lysine and asparagine residues found among all PLD family members.
| + | The line below this paragraph, {{ABSTRACT_PUBMED_15111055}}, adds the Publication Abstract to the page |
| | + | (as it appears on PubMed at http://www.pubmed.gov), where 15111055 is the PubMed ID number. |
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| | + | {{ABSTRACT_PUBMED_15111055}} |
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| | ==About this Structure== | | ==About this Structure== |
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| | [[Category: Dna repair]] | | [[Category: Dna repair]] |
| | [[Category: Replication]] | | [[Category: Replication]] |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 06:54:00 2008'' | + | |
| | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Jul 27 13:13:57 2008'' |
Revision as of 10:14, 27 July 2008
Template:STRUCTURE 1qzq
human Tyrosyl DNA phosphodiesterase
Template:ABSTRACT PUBMED 15111055
About this Structure
1QZQ is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Analysis of human tyrosyl-DNA phosphodiesterase I catalytic residues., Raymond AC, Rideout MC, Staker B, Hjerrild K, Burgin AB Jr, J Mol Biol. 2004 May 14;338(5):895-906. PMID:15111055
Page seeded by OCA on Sun Jul 27 13:13:57 2008
