1znv
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1znv.gif|left|200px]] | [[Image:1znv.gif|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1znv", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | + | {{STRUCTURE_1znv| PDB=1znv | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''How a His-metal finger endonuclease ColE7 binds and cleaves DNA with a transition metal ion cofactor''' | '''How a His-metal finger endonuclease ColE7 binds and cleaves DNA with a transition metal ion cofactor''' | ||
| Line 32: | Line 29: | ||
[[Category: Shi, Z.]] | [[Category: Shi, Z.]] | ||
[[Category: Yuan, H S.]] | [[Category: Yuan, H S.]] | ||
| - | [[Category: | + | [[Category: Endonuclease]] |
| - | [[Category: | + | [[Category: H-n-h motif]] |
| - | [[Category: | + | [[Category: Ni-binding]] |
| - | [[Category: | + | [[Category: Protein-protein complex]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May 3 17:51:32 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 14:51, 3 May 2008
How a His-metal finger endonuclease ColE7 binds and cleaves DNA with a transition metal ion cofactor
Overview
The nuclease domain of ColE7 (N-ColE7) contains an H-N-H motif that folds in a beta beta alpha-metal topology. Here we report the crystal structures of a Zn2+-bound N-ColE7 (H545E mutant) in complex with a 12-bp duplex DNA and a Ni2+-bound N-ColE7 in complex with the inhibitor Im7 at a resolution of 2.5 A and 2.0 A, respectively. Metal-dependent cleavage assays showed that N-ColE7 cleaves double-stranded DNA with a single metal ion cofactor, Ni2+, Mg2+, Mn2+, and Zn2+. ColE7 purified from Escherichia coli contains an endogenous zinc ion that was not replaced by Mg2+ at concentrations of <25 mM, indicating that zinc is the physiologically relevant metal ion in N-ColE7 in host E. coli. In the crystal structure of N-ColE7/DNA complex, the zinc ion is directly coordinated to three histidines and the DNA scissile phosphate in a tetrahedral geometry. In contrast, Ni2+ is bound in N-ColE7 in two different modes, to four ligands (three histidines and one phosphate ion), or to five ligands with an additional water molecule. These data suggest that the divalent metal ion in the His-metal finger motif can be coordinated to six ligands, such as Mg2+ in I-PpoI, Serratia nuclease and Vvn, five ligands or four ligands, such as Ni2+ or Zn2+ in ColE7. Universally, the metal ion in the His-metal finger motif is bound to the DNA scissile phosphate and serves three roles during hydrolysis: polarization of the P-O bond for nucleophilic attack, stabilization of the phosphoanion transition state and stabilization of the cleaved product.
About this Structure
1ZNV is a Protein complex structure of sequences from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Crystal structural analysis and metal-dependent stability and activity studies of the ColE7 endonuclease domain in complex with DNA/Zn2+ or inhibitor/Ni2+., Doudeva LG, Huang H, Hsia KC, Shi Z, Li CL, Shen Y, Cheng YS, Yuan HS, Protein Sci. 2006 Feb;15(2):269-80. PMID:16434744 Page seeded by OCA on Sat May 3 17:51:32 2008
