View source for 2nq9

[[Image:2nq9.gif|left|200px]]

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{{STRUCTURE_2nq9|  PDB=2nq9  |  SCENE=  }} 

'''High resolution crystal structure of Escherichia coli endonuclease IV (Endo IV) Y72A mutant bound to damaged DNA'''


==Overview==
Escherichia coli endonuclease IV is an archetype for an abasic or apurinic-apyrimidinic endonuclease superfamily crucial for DNA base excision repair. Here biochemical, mutational and crystallographic characterizations reveal a three-metal ion mechanism for damage binding and incision. The 1.10-A resolution DNA-free and the 2.45-A resolution DNA-substrate complex structures capture substrate stabilization by Arg37 and reveal a distorted Zn(3)-ligand arrangement that reverts, after catalysis, to an ideal geometry suitable to hold rather than release cleaved DNA product. The 1.45-A resolution DNA-product complex structure shows how Tyr72 caps the active site, tunes its dielectric environment and promotes catalysis by Glu261-activated hydroxide, bound to two Zn(2+) ions throughout catalysis. These structural, mutagenesis and biochemical results suggest general requirements for abasic site removal in contrast to features specific to the distinct endonuclease IV alpha-beta triose phosphate isomerase (TIM) barrel and APE1 four-layer alpha-beta folds of the apurinic-apyrimidinic endonuclease families.

==About this Structure==
2NQ9 is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2NQ9 OCA]. 

==Reference==
DNA apurinic-apyrimidinic site binding and excision by endonuclease IV., Garcin ED, Hosfield DJ, Desai SA, Haas BJ, Bjoras M, Cunningham RP, Tainer JA, Nat Struct Mol Biol. 2008 Apr 13;. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/18408731 18408731]
[[Category: Escherichia coli]]
[[Category: Single protein]]
[[Category: Garcin-Hosfield, E D.]]
[[Category: Hosfield, D J.]]
[[Category: Tainer, J A.]]
[[Category: Hydrolase/dna complex]]
[[Category: Tim-barrel]]
[[Category: Trinuclear zn active site]]
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Apr 24 09:25:13 2008''