1mht: Difference between revisions

Revision as of 01:03, 3 May 2008

COVALENT TERNARY STRUCTURE OF HHAI METHYLTRANSFERASE, DNA AND S-ADENOSYL-L-HOMOCYSTEINE

OverviewOverview

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.

About this StructureAbout this Structure

1MHT is a Single protein structure of sequence from Haemophilus haemolyticus. Full crystallographic information is available from OCA.

ReferenceReference

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 Page seeded by OCA on Sat May 3 01:03:47 2008

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

OCA

@@ Line 1: / Line 1: @@
 [[Image:1mht.jpg|left|200px]]
- {{Structure
+<!--
-|PDB= 1mht |SIZE=350|CAPTION= <scene name='initialview01'>1mht</scene>, resolution 2.60&Aring;
+The line below this paragraph, containing "STRUCTURE_1mht", creates the "Structure Box" on the page.
-|SITE=
+You may change the PDB parameter (which sets the PDB file loaded into the applet)
-|LIGAND= <scene name='pdbligand=C36:5-METHYL-5-FLUORO-2&#39;-DEOXY-CYTIDINE-5&#39;-MONOPHOSPHATE'>C36</scene>, <scene name='pdbligand=DA:2&#39;-DEOXYADENOSINE-5&#39;-MONOPHOSPHATE'>DA</scene>, <scene name='pdbligand=DC:2&#39;-DEOXYCYTIDINE-5&#39;-MONOPHOSPHATE'>DC</scene>, <scene name='pdbligand=DG:2&#39;-DEOXYGUANOSINE-5&#39;-MONOPHOSPHATE'>DG</scene>, <scene name='pdbligand=DT:THYMIDINE-5&#39;-MONOPHOSPHATE'>DT</scene>, <scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene>
+or the SCENE parameter (which sets the initial scene displayed when the page is loaded),
-|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Deleted_entry Deleted entry], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.73 2.1.1.73] </span>
+or leave the SCENE parameter empty for the default display.
-|GENE=
+-->
-|DOMAIN=
+{{STRUCTURE_1mht|  PDB=1mht  |  SCENE=  }}
-|RELATEDENTRY=
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1mht FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1mht OCA], [http://www.ebi.ac.uk/pdbsum/1mht PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1mht RCSB]</span>
-}}
 '''COVALENT TERNARY STRUCTURE OF HHAI METHYLTRANSFERASE, DNA AND S-ADENOSYL-L-HOMOCYSTEINE'''
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 [[Category: Single protein]]
 [[Category: Cheng, X.]]
-[[Category: double helix]]
+[[Category: Double helix]]
-[[Category: flipped-out base]]
+[[Category: Flipped-out base]]
-[[Category: modified]]
+[[Category: Modified]]
-[[Category: overhanging base]]
+[[Category: Overhanging base]]
-[[Category: protein-dna complex]]
+[[Category: Protein-dna complex]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sat May  3 01:03:47 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 22:16:15 2008''