1fjx

<table><tr><td colspan='2'>[[1fjx]] is a 3 chain structure with sequence from [https://en.wikipedia.org/wiki/"bacillus_x"_pritchett_and_stillman_1919 "bacillus x" pritchett and stillman 1919]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1FJX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1FJX FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=SAH:S-ADENOSYL-L-HOMOCYSTEINE'>SAH</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene></td></tr>

<tr id='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat"><div style='overflow: auto; max-height: 3em;'>[[3mht|3mht]]</div></td></tr>

<tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/DNA_(cytosine-5-)-methyltransferase DNA (cytosine-5-)-methyltransferase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.1.1.37 2.1.1.37] </span></td></tr>

[[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.

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== Publication Abstract from PubMed ==

DNA cytosine-5-methyltransferase HhaI recognizes the GCGC sequence and flips the inner cytosine out of DNA helix and into the catalytic site for methylation. The 5'-phosphate of the flipped out cytosine is in contact with the conserved Thr-250 from the target recognition domain. We have produced 12 mutants of Thr-250 and examined their methylation potential in vivo. Six active mutants were subjected to detailed biochemical and structural studies. Mutants with similar or smaller side chains (Ser, Cys, and Gly) are very similar to wild-type enzyme in terms of steady-state kinetic parameters k(cat), K(m)(DNA), K(m)(AdoMet). In contrast, the mutants with bulkier side chains (Asn, Asp, and His) show increased K(m) values for both substrates. Fluorescence titrations and stopped-flow kinetic analysis of interactions with duplex oligonucleotides containing 2-aminopurine at the target base position indicate that the T250G mutation leads to a more polar but less solvent-accessible position of the flipped out target base. The x-ray structure of the ternary M. HhaI(T250G).DNA.AdoHcy complex shows that the target cytosine is locked in the catalytic center of enzyme. The space created by the mutation is filled by water molecules and the adjacent DNA backbone atoms dislocate slightly toward the missing side chain. In aggregate, our results suggest that the side chain of Thr-250 is involved in constraining the conformation the DNA backbone and the target base during its rotation into the catalytic site of enzyme.

Functional roles of the conserved threonine 250 in the target recognition domain of HhaI DNA methyltransferase.,Vilkaitis G, Dong A, Weinhold E, Cheng X, Klimasauskas S J Biol Chem. 2000 Dec 8;275(49):38722-30. PMID:11102456<ref>PMID:11102456</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 1fjx" style="background-color:#fffaf0;"></div>

== References ==

<references/>

[[Category: Bacillus x pritchett and stillman 1919]]

[[Category: Cheng, X]]

[[Category: Dong, A]]

[[Category: Klimasauskas, S]]

[[Category: Vilkaitis, G]]

[[Category: Weinhold, E]]

[[Category: Transferase-dna complex]]