Hexacyanochromate ion as a paramagnetic anion probe for active sites of enzymes
Abstract:
Hexacyanochromate ion, (Cr(CN)6)3-, was applied to ribonuclease T1 (RNase T1), which specifically cleaves RNA chains at guanylic acid residues. From kinetic studies, this anion was shown to bind to the active site of RNase T1 as a competitive inhibitor. Therefore, the line broadening effect of NMR resonances due to binding of (Cr(CN)6)3- was analyzed for the mapping of the active site of RNase T1. His-40 C2 proton resonance was significantly broadened, following His-92 C2 proton resonance upon binding of (Cr(CN)6)3-, while His-27 C2 proton resonance did not show any appreciable line broadening. Moreover, from the pH dependence of the line broadening effect, the binding of (Cr(CN)6)3- was shown to be controlled by the ionic state of Glu-58. Based on the present NMR results and x-ray crystal structure, the active site structure of RNase T1 is discussed.
More Related Videos
07:24Paramagnetic Relaxation Enhancement for Detecting and Characterizing Self-Associations of Intrinsically Disordered Proteins
Published on: September 23, 2021
06:53Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
Related Concept Videos
03:02Colors and Magnetism
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human eye.
01:13Introduction to Mechanisms of Enzyme Catalysis
01:22EDTA: Chemistry and Properties
01:26EDTA: Auxiliary Complexing Reagents