Structural dynamics of heme–copper oxidases and nitric oxide reductases: time‐resolved step‐scan Fourier transform infrared and time‐resolved resonance Raman studies

Abstract

Of the spectroscopic methods available for the characterization of the dynamics of heme protein active sites, time-resolved resonance Raman spectroscopy (TR 3 ) is a powerful technique because excitation within the heme p-p * electronic absorption transitions selectively enhances vibrational modes of the heme and bound-proximal/distal ligands without the interference from the modes associated with the protein matrix. On the other hand, time-resolved step-scan (TRS 2 ) Fourier transform infrared (FTIR) spectroscopy has the sensitivity and resolution to detect, in addition to ligands bound to metal centers and the kinetics of ligand photodissociation, transient changes at the level of individual amino acids during protein action.This review outlines the application of both TR 3 and TRS 2 -FTIR to heme-copper oxidases and nitric oxide reductases.

Nitric oxide activation and reduction by heme–copper oxidoreductases and nitric oxide reductase

“…The computed m N-N frequency at 1252 cm -1 , exhibits 15 N isotope sensitivity (Dm = 36 cm À1 ), and the 14 N 18 O isotope does not affect the frequency significantly. Indeed, the N-N vibration which is detected only by UV excitation is not affected by 18 O isotope substitution. This observation further supports our assignment and excludes the possible assignment to an N-O stretch.…”

“…The sequence of NorB contains all six histidines which are the ligands of heme a, heme a 3 and Cu B in cytochrome c oxidase [1][2][3][4][5]. Resonance Raman (RR) and time-resolved RR have revealed the properties of the dinuclear center of oxidized, reduced, CO-and NO-bound Nor from Paracoccus denitrificans [11,17,18]. The spectra of the oxidized enzyme showed two distinct m as (Fe-O-Fe) modes at 813 and 833 cm À1 that have been attributed to two different conformations (open and closed) of the catalytic site of the enzyme [11].…”

Recent Advances in linear and nonlinear Raman spectroscopy I

“…Tuma 157 reviewed recent developments in peptide and protein Raman spectroscopy, including the application of infrared and vibrational circular dichroism. 160 Several papers were devoted to heme protein research. A theoretical study on peptide/protein-related research was published by Kwac and Cho.…”

Reliability of fourier transform infrared spectroscopy in the characterization of human skin

“…Monosaccharides, homopolysaccharides, glycosaminoglycans (GAG's) and amino acids have been characterized, using IR spectroscopy [2][3][4]. This technique has also been employed successfully in the analysis of age-mediated GAG alterations [5], elucidation of protein secondary structure [6], and protein conformational changes during reaction [7,8]. Its value in determining relative hydration states of hyaluronic acid (hyaluronan, HA) and chondroitin sulfate have been demonstrated [9].…”