3m7k

<StructureSection load='3m7k' size='340' side='right' caption='[[3m7k]], [[Resolution|resolution]] 1.92&Aring;' scene=''>

<table><tr><td colspan='2'>[[3m7k]] is a 3 chain structure with sequence from [http://en.wikipedia.org/wiki/Atcc_14909 Atcc 14909]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3M7K OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3M7K FirstGlance]. <br>

</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=PT:PLATINUM+(II)+ION'>PT</scene>, <scene name='pdbligand=SO4:SULFATE+ION'>SO4</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</scene></td></tr>

<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">pacIR ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=43263 ATCC 14909])</td></tr>

<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3m7k FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3m7k OCA], [http://pdbe.org/3m7k PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=3m7k RCSB], [http://www.ebi.ac.uk/pdbsum/3m7k PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=3m7k ProSAT]</span></td></tr>

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== Publication Abstract from PubMed ==

The crystal structure of the rare-cutting HNH restriction endonuclease PacI in complex with its eight-base-pair target recognition sequence 5'-TTAATTAA-3' has been determined to 1.9 A resolution. The enzyme forms an extended homodimer, with each subunit containing two zinc-bound motifs surrounding a betabetaalpha-metal catalytic site. The latter is unusual in that a tyrosine residue likely initiates strand cleavage. PacI dramatically distorts its target sequence from Watson-Crick duplex DNA base pairing, with every base separated from its original partner. Two bases on each strand are unpaired, four are engaged in noncanonical A:A and T:T base pairs, and the remaining two bases are matched with new Watson-Crick partners. This represents a highly unusual DNA binding mechanism for a restriction endonuclease, and implies that initial recognition of the target site might involve significantly different contacts from those visualized in the DNA-bound cocrystal structures.

 

== References ==

[[Category: Atcc 14909]]

[[Category: Shen, B W]]

[[Category: Stoddard, B L]]

[[Category: Base-pair rare cutter]]

[[Category: Hydrolase-dna complex]]