View source for 1mht


==COVALENT TERNARY STRUCTURE OF HHAI METHYLTRANSFERASE, DNA AND S-ADENOSYL-L-HOMOCYSTEINE==
<StructureSection load='1mht' size='340' side='right'caption='[[1mht]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1mht]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/Haemophilus_haemolyticus Haemophilus haemolyticus]. The July 2011 RCSB PDB [https://pdb.rcsb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/index.html Molecule of the Month] feature on ''DNA Methylases''  by David Goodsell is [https://dx.doi.org/10.2210/rcsb_pdb/mom_2011_7 10.2210/rcsb_pdb/mom_2011_7]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1MHT OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1MHT FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=C36:5-METHYL-5-FLUORO-2-DEOXY-CYTIDINE-5-MONOPHOSPHATE'>C36</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=1mht FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mht OCA], [https://pdbe.org/1mht PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1mht RCSB], [https://www.ebi.ac.uk/pdbsum/1mht PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1mht ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/MTH1_HAEPH MTH1_HAEPH] This methylase recognizes the double-stranded sequence GCGC, causes specific methylation on C-2 on both strands, and protects the DNA from cleavage by the HhaI endonuclease.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/mh/1mht_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1mht ConSurf].
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== Publication Abstract from PubMed ==
The crystal structure has been determined at 2.8 A resolution for a chemically-trapped covalent reaction intermediate between the HhaI DNA cytosine-5-methyltransferase, S-adenosyl-L-homocysteine, and a duplex 13-mer DNA oligonucleotide containing methylated 5-fluorocytosine at its target. The DNA is located in a cleft between the two domains of the protein and has the characteristic conformation of B-form DNA, except for a disrupted G-C base pair that contains the target cytosine. The cytosine residue has swung completely out of the DNA helix and is positioned in the active site, which itself has undergone a large conformational change. The DNA is contacted from both the major and the minor grooves, but almost all base-specific interactions between the enzyme and the recognition bases occur in the major groove, through two glycine-rich loops from the small domain. The structure suggests how the active nucleophile reaches its target, directly supports the proposed mechanism for cytosine-5 DNA methylation, and illustrates a novel mode of sequence-specific DNA recognition.

HhaI methyltransferase flips its target base out of the DNA helix.,Klimasauskas S, Kumar S, Roberts RJ, Cheng X Cell. 1994 Jan 28;76(2):357-69. PMID:8293469<ref>PMID:8293469</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 1mht" style="background-color:#fffaf0;"></div>

==See Also==
*[[DNA methyltransferase 3D structures|DNA methyltransferase 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: DNA Methylases]]
[[Category: Haemophilus haemolyticus]]
[[Category: Large Structures]]
[[Category: RCSB PDB Molecule of the Month]]
[[Category: Cheng X]]