Design of peptide-acridine mimics of ribonuclease activity.
A series of peptide-acridine conjugates was designed and synthesized, based on three features of the proposed catalytic mechanism of RNase A: 2'-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.
Tung
C H
CH
Center for Advanced Biotechnology, Rutgers University, Piscataway, NJ 08854.
Wei
Z
Z
Leibowitz
M J
MJ
Stein
S
S
D000166:Acridines / Q000737:chemistry*; D000595:Amino Acid Sequence; D002384:Catalysis; D002850:Chromatography, Gel; D008969:Molecular Sequence Data; D009691:Nucleic Acid Denaturation; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry*; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D012335:RNA, Ribosomal / Q000737:chemistry / Q000378:metabolism; D012260:Ribonucleases / Q000378:metabolism*; D013329:Structure-Activity Relationship
D000166:Acridines; D009842:Oligopeptides; D012335:RNA, Ribosomal; D012313:RNA; D012260:Ribonucleases