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PubMed · 9171286

Small-molecule-substrate interactions with a self-aminoacylating ribozyme.

M Illangasekare·M Yarus
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Abstract

A self-aminoacylating RNA catalyst is shown to carry out the chemistry required for turnover, being reacylated several times from aminoacyl-AMP with an unaltered rate, thereby meeting one definition of an enzyme. Furthermore, a newly applied gel electrophoresis assay suggests first order kinetics in RNA and saturation kinetics in the substrate aminoacyl-adenylate, implying a Michaelis complex. AMP is a competitive inhibitor, though phenylalanine is not detectably inhibitory, consistent with a Michaelis complex through the AMP moiety of phenylalanyl-adenylate substrate. This idea is supported by measurement of elevated acylation velocities with seryl and alanyl-adenylates. The rate of aminoacylation increases with pH, consistent with attack of a terminal ribose oxyanion on the carbonyl carbon atom of the adenylate.

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AcylationAdenosine MonophosphateAmino AcidsCatalysisElectrophoresis, Polyacrylamide GelHydrogen-Ion ConcentrationKineticsMolecular Sequence DataNucleic Acid ConformationRNA, CatalyticSodium ChlorideJournal ArticleResearch Support, U.S. Gov't, P.H.S.

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M Illangasekare, M Yarus. 1997-05-09. Small-molecule-substrate interactions with a self-aminoacylating ribozyme.. https://doi.org/10.1006/jmbi.1997.0988

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