Vibrational spectroscopies and bioenergetic systems

PMID: 25448165Infrared and Raman spectroscopies are sensitive methods for the study of the chemical composition and the architecture of molecules. The high information content in infrared and Raman spectra was carried over from classical approaches in analytical chemistry to the study on biological systems and became an important tool for the study of proteins that are in focus of the field of molecular bioenergetics. The full potential of vibrational spectroscopies unfolds when isotopic labeling and site-directed mutagenesis are used to allow an unequivocal assignment of absorption bands or when the high structural information content are used in combination with high time resolution. The techniques are thus ideally suited to study the molecular mechanism of protein reactions. In this Special Issue of BBA Bioenergetics, a variety of timely topics related the study of bioenergetic systems by means of vibrational spectroscopies is reviewed. This issue aims to present a collection of many, but certainly not all, applications of the techniques in the field. The topics of the articles range from key aspects of the core structure–function relationships through the molecular mechanisms of catalytic sites in enzymes from photosynthesis and respiration. Studies are presented which give insight into the proton pump mechanisms of proteins, coupled electron and proton transfer and ligand binding to the active sites in enzymes or in biomimetic models. They also highlight the strength of vibrational spectroscopic techniques when it comes to monitor the reaction or the structural environment of specific molecules like protonatable amino acid side chains, tyrosines, quinones or carotenoids. Ultrafast vibrational spectroscopies, studies at equilibrium, reaction induced FTIR difference spectroscopies, resonance Raman and Fluorescence Line-Narrowing, are presented in this Special Issue, giving an impressing insight into the opportunities vibrational spectroscopies will also provide in the future for the study of the complex and fascinating systems that rule respiration and photosynthesis