429d: Difference between revisions
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[[ | ==CRYSTAL STRUCTURE OF A LEADZYME; METAL BINDING AND IMPLICATIONS FOR CATALYSIS== | ||
<StructureSection load='429d' size='340' side='right' caption='[[429d]], [[Resolution|resolution]] 2.70Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[429d]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=429D OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=429D FirstGlance]. <br> | |||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=MG:MAGNESIUM+ION'>MG</scene></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=429d FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=429d OCA], [http://www.rcsb.org/pdb/explore.do?structureId=429d RCSB], [http://www.ebi.ac.uk/pdbsum/429d PDBsum]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The leadzyme is a small RNA motif that catalyzes a site-specific, Pb2+-dependent cleavage reaction. As such, it is an example of a metal-dependent RNA enzyme. Here we describe the X-ray crystallographic structure of the leadzyme, which reveals two independent molecules per asymmetric unit. Both molecules feature an internal loop in which a bulged purine base stack twists away from the helical stem. This kinks the backbone, rendering the phosphodiester bond susceptible to cleavage. The independent molecules have different conformations: one leadzyme copy coordinates Mg2+, whereas the other binds only Ba2+ or Pb2+. In the active site of the latter molecule, a single Ba2+ ion coordinates the 2'-OH nucleophile, and appears to mimic the binding of catalytic lead. These observations allow a bond cleavage reaction to be modeled, which reveals the minimal structural features necessary for catalysis by this small ribozyme. | |||
Crystal structure of a lead-dependent ribozyme revealing metal binding sites relevant to catalysis.,Wedekind JE, McKay DB Nat Struct Biol. 1999 Mar;6(3):261-8. PMID:10074945<ref>PMID:10074945</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Ribozyme|Ribozyme]] | *[[Ribozyme|Ribozyme]] | ||
== References == | |||
== | <references/> | ||
< | __TOC__ | ||
[[Category: McKay, D. B | </StructureSection> | ||
[[Category: Wedekind, J. E | [[Category: McKay, D. B]] | ||
[[Category: Wedekind, J. E]] | |||
[[Category: Bulged nucleotide]] | [[Category: Bulged nucleotide]] | ||
[[Category: Lead-dependent cleavage]] | [[Category: Lead-dependent cleavage]] | ||
