Kinetic and Thermodynamic Analysis of RNA-Protein Interactions in the RNase P Holoenzyme from Escherichia coli

Simon J. Talbot, Sidney Altman

Research output: Contribution to journalArticle

47 Scopus citations

Abstract

A gel retardation assay has been used to examine the kinetic and equilibrium properties of the interaction between C5 protein and M1 RNA in the formation of the ribonuclease P holoenzyme from Escherichia coli. The interaction is relatively insensitive to the identity of the monovalent anions present and to pH in the range 7.0–9.0, but it has a more critical requirement for specific monovalent and divalent cations: NH4+, K+, Mg2+, Ca2+, and Mn2+ all promote efficient formation of the complex. A positive ΔS (+6.4 cal mol−1 deg−1) and a negative ΔH (-11.3 kcal mol−1) combine to give a ΔG equal to -13.3 kcal mol−1 at 37 °C in 0.42 M salt. The binding reaction is sensitive to the concentration of monovalent and divalent cations, with the affinity increasing with increasing ionic strength (δ log Ka/δ log [NH4+] = +2.7 ± 0.1). The dependence of Kd on the ionic strength and the positive ΔS suggests that hydrophobic and stacking interactions contribute significantly to the formation of the RNase P holoenzyme.

Original languageEnglish (US)
Pages (from-to)1406-1411
Number of pages6
JournalBiochemistry
Volume33
Issue number6
DOIs
StatePublished - Feb 1 1994
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'Kinetic and Thermodynamic Analysis of RNA-Protein Interactions in the RNase P Holoenzyme from Escherichia coli'. Together they form a unique fingerprint.

  • Cite this