2aoq: Difference between revisions

Revision as of 17:29, 21 February 2008

Crystal structure of MutH-unmethylated DNA complex

OverviewOverview

MutH initiates mismatch repair by nicking the transiently unmethylated daughter strand 5' to a GATC sequence. Here, we report crystal structures of MutH complexed with hemimethylated and unmethylated GATC substrates. Both structures contain two Ca2+ ions jointly coordinated by a conserved aspartate and the scissile phosphate, as observed in the restriction endonucleases BamHI and BglI. In the hemimethylated complexes, the active site is more compact and DNA cleavage is more efficient. The Lys residue in the conserved DEK motif coordinates the nucleophilic water in conjunction with the phosphate 3' to the scissile bond; the same Lys is also hydrogen bonded with a carbonyl oxygen in the DNA binding module. We propose that this Lys, which is conserved in many restriction endonucleases and is replaced by Glu or Gln in BamHI and BglII, is a sensor for DNA binding and the linchpin that couples base recognition and DNA cleavage.

About this StructureAbout this Structure

2AOQ is a Single protein structure of sequence from Haemophilus influenzae with as ligand. Full crystallographic information is available from OCA.

ReferenceReference

MutH complexed with hemi- and unmethylated DNAs: coupling base recognition and DNA cleavage., Lee JY, Chang J, Joseph N, Ghirlando R, Rao DN, Yang W, Mol Cell. 2005 Oct 7;20(1):155-66. PMID:16209953

Page seeded by OCA on Thu Feb 21 16:29:28 2008

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OCA

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-[[Image:2aoq.gif|left|200px]]<br /><applet load="2aoq" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:2aoq.gif|left|200px]]<br /><applet load="2aoq" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="2aoq, resolution 2.20&Aring;" />
 '''Crystal structure of MutH-unmethylated DNA complex'''<br />
 ==Overview==
-MutH initiates mismatch repair by nicking the transiently unmethylated, daughter strand 5' to a GATC sequence. Here, we report crystal structures, of MutH complexed with hemimethylated and unmethylated GATC substrates., Both structures contain two Ca2+ ions jointly coordinated by a conserved, aspartate and the scissile phosphate, as observed in the restriction, endonucleases BamHI and BglI. In the hemimethylated complexes, the active, site is more compact and DNA cleavage is more efficient. The Lys residue, in the conserved DEK motif coordinates the nucleophilic water in, conjunction with the phosphate 3' to the scissile bond; the same Lys is, also hydrogen bonded with a carbonyl oxygen in the DNA binding module. We, propose that this Lys, which is conserved in many restriction, endonucleases and is replaced by Glu or Gln in BamHI and BglII, is a, sensor for DNA binding and the linchpin that couples base recognition and, DNA cleavage.
+MutH initiates mismatch repair by nicking the transiently unmethylated daughter strand 5' to a GATC sequence. Here, we report crystal structures of MutH complexed with hemimethylated and unmethylated GATC substrates. Both structures contain two Ca2+ ions jointly coordinated by a conserved aspartate and the scissile phosphate, as observed in the restriction endonucleases BamHI and BglI. In the hemimethylated complexes, the active site is more compact and DNA cleavage is more efficient. The Lys residue in the conserved DEK motif coordinates the nucleophilic water in conjunction with the phosphate 3' to the scissile bond; the same Lys is also hydrogen bonded with a carbonyl oxygen in the DNA binding module. We propose that this Lys, which is conserved in many restriction endonucleases and is replaced by Glu or Gln in BamHI and BglII, is a sensor for DNA binding and the linchpin that couples base recognition and DNA cleavage.
 ==About this Structure==
-AOQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae] with CA as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2AOQ OCA].
+AOQ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Haemophilus_influenzae Haemophilus influenzae] with <scene name='pdbligand=CA:'>CA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2AOQ OCA].
 ==Reference==
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 [[Category: Ghirlando, R.]]
 [[Category: Joseph, N.]]
-[[Category: Lee, J.Y.]]
+[[Category: Lee, J Y.]]
-[[Category: Rao, D.N.]]
+[[Category: Rao, D N.]]
 [[Category: Yang, W.]]
 [[Category: CA]]
 [[Category: gatc recognition]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 08:15:38 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:29:28 2008''