A simple procedure for resolution of Escherichia coli RNA polymerase holoenzyme from core polymerase. |
| |
Authors: | N Gonzalez J Wiggs M J Chamberlin |
| |
Affiliation: | Cardiovascular Research Institute, University of California, San Francisco, California 94143 USA |
| |
Abstract: | The association constant, KA, for myosin subfragment-1 binding to actin was measured as a function of ionic strength [KCl, LiCl, and tetramethylammonium chloride (TMAC)]and temperature by the method of time-resolved fluorescence depolarization. The following thermodynamic values were obtained from solutions of 0.20 × 10?6m S-1, 1.00 × 10?6m actin in 0.15 m KCl, pH 7.0, at 25 °C: ΔG ° = ?39 ± 1 kJ M?1, ΔH0 = 44 ± 2 kJ M?1 and . For measurements in KCl (0.05 to 0.60 m), In . Thus, the binding is endothermic and strongly inhibited by high ionic strength. When KCl was replaced by LiCl or TMAC the ionic effects on the binding were cation specific. The nature of actin-(S-1) binding in the rigor state is discussed in terms of these results. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |
|