Document Detail


Ligand-pKa shifts through metals: potential relevance to ribozyme chemistry.
MedLine Citation:
PMID:  18729108     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Functional and crystallographic analyses of catalytically active RNA molecules ('ribozymes') have revealed a multitude of different routes by which nature accomplishes cleavage reactions of the RNA sugar-phosphate backbone. While there is agreement that these reactions involve general acid-base chemistry, the choice of 'acid' and of 'base' appears to be quite versatile. Among the numerous surprises that have emerged from these studies in recent years is the phenomenon of 'shifted pK(a) values' of nucleobases, hence, the fact that pK(a) values of isolated nucleobases in H(2)O can be shifted in either direction--upward or downward--into the physiological pH range, and that consequently allows these nucleobases to function as 'acids' or 'bases'. Another change in paradigm in recent years relates to the role of divalent metal ions in these catalytic reactions, which points to the possibility of an indirect involvement in the catalytic cycle rather than necessarily to a direct participation, as in the case with the hepatitis delta virus ribozyme. In this review, basic features of nucleobases and/or aqua ligand pK(a) shifts caused by metal coordination and H-bonding are discussed.
Authors:
Bernhard Lippert
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Review    
Journal Detail:
Title:  Chemistry & biodiversity     Volume:  5     ISSN:  1612-1880     ISO Abbreviation:  Chem. Biodivers.     Publication Date:  2008 Aug 
Date Detail:
Created Date:  2008-09-02     Completed Date:  2008-12-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101197449     Medline TA:  Chem Biodivers     Country:  Switzerland    
Other Details:
Languages:  eng     Pagination:  1455-74     Citation Subset:  IM    
Affiliation:
Fakultät Chemie, Technische Universität Dortmund, Otto-Hahn-Strasse 6, D-44227 Dortmund. bernhard.lippert@tu-dortmund.de
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MeSH Terms
Descriptor/Qualifier:
Hydrogen Bonding
Hydrogen-Ion Concentration
Ligands
Metals / chemistry*
Organometallic Compounds / chemistry*
RNA, Catalytic / chemistry*,  physiology
Chemical
Reg. No./Substance:
0/Ligands; 0/Metals; 0/Organometallic Compounds; 0/RNA, Catalytic

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