@article{TEXTUAL,
      recid = {10189},
      author = {Hougland, James L. and Kravchuk, Alexander V. and  Herschlag, Daniel and Piccirilli, Joseph A.},
      title = {Functional Identification of Catalytic Metal Ion Binding  Sites within RNA},
      journal = {PLOS Biology},
      address = {2005-08-16},
      number = {TEXTUAL},
      abstract = {&lt;p&gt;The viability of living systems depends inextricably on  enzymes that catalyze phosphoryl transfer reactions. For  many enzymes in this class, including several ribozymes,  divalent metal ions serve as obligate cofactors.  Understanding how metal ions mediate catalysis requires  elucidation of metal ion interactions with both the enzyme  and the substrate(s). In the &lt;em&gt;Tetrahymena&lt;/em&gt; group I  intron, previous work using atomic mutagenesis and  quantitative analysis of metal ion rescue behavior  identified three metal ions (M&lt;sub&gt;A&lt;/sub&gt;, M&lt;sub&gt;B&lt;/sub&gt;,  and M&lt;sub&gt;C&lt;/sub&gt;) that make five interactions with the  ribozyme substrates in the reaction's transition state.  Here, we combine substrate atomic mutagenesis with  site-specific phosphorothioate substitutions in the  ribozyme backbone to develop a powerful, general strategy  for defining the ligands of catalytic metal ions within  RNA. In applying this strategy to the &lt;em&gt;Tetrahymena&lt;/em&gt;  group I intron, we have identified the  &lt;em&gt;pro-S&lt;/em&gt;&lt;sub&gt;P&lt;/sub&gt; phosphoryl oxygen at nucleotide  C262 as a ribozyme ligand for M&lt;sub&gt;C&lt;/sub&gt;. Our findings  establish a direct connection between the ribozyme core and  the functionally defined model of the chemical transition  state, thereby extending the known set of transition-state  interactions and providing information critical for the  application of the recent group I intron crystallographic  structures to the understanding of catalysis.&lt;/p&gt;},
      url = {http://knowledge.uchicago.edu/record/10189},
}