A series of peptide-acridine conjugates was designed and synthesized, based on three features of the proposed catalytic mechanism of RNase A: 2prime;-proton abstraction by His-12, proton donation to the leaving 5′-oxygen by His-119, and stabilization of the pentacoordinated phosphorous transition state by Lys-41. The substrate binding capability of RNase A was mimicked by the intercalator, acridine. Lysine served as a linker between acridine and the catalytic tripeptide. Cleavage of target RNA was monitored by agarose gel electrophoresis and by gel-permeation chromatography. The carboxyl-amidated conjugates HGHK(Acr)-NH2, HPHK(Acr)-NH2, and GGHK(Acr)-NH2 (where Acr indicates 2-methyl-9-acridinemethylene) all had similar hydrolytic activity. The catalytic mechanism most likely involved only the abstraction of the 2′-proton and stabilization of the transition state. These RNase mimics utilized rRNA and single-stranded RNA but not double-stranded RNA and tRNA as substrates.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1992|
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