Proton-coupled electron transfer (PCET) is an important mechanism for charge transfer in a wide variety of systems including biology- and materials-oriented venues. We review several areas where the transfer of an electron and proton is tightly coupled and discuss model systems that can provide an experimental basis for a test of PCET theory. In a PCET reaction, the electron and proton may tran...

Nitroaromatic compounds, ArNO2 have widespread actual or potential use in medicine and cancer therapy. There is direct proof that free-radical metabolites are involved in many applications, and an appreciation of the conceptual basis for their therapeutic differential; however, an understanding of the detailed mechanisms involved is lacking. Redox properties control most biological responses of...

Rhodobacter species are useful model organisms for studying the structure and function of c type cytochromes (Cyt c), which are ubiquitous electron carriers with essential functions in cellular energy and signal transduction. Among these species, Rhodobacter capsulatus has a periplasmic Cyt c2Rc and a membrane-bound bipartite Cyt cyRc. These electron carriers participate in both respiratory and...

Three types of oxidation-reduction (redox) centers are found in biology: protein side chains, small molecules, and redox cofactors. The first class is frequently overlooked by mechanistic enzymologists. The sulfhydryl group of cysteine is easily oxidized to produce a dimer, known as cystine:-2e This type of interconversion is known to occur in several redox proteins, including xanthine oxidase,...

Recent investigations have shed much light on the nuclear and electronic factors that control the rates of long-range electron tunneling through molecules in aqueous and organic glasses as well as through bonds in donor-bridge-acceptor complexes. Couplings through covalent and hydrogen bonds are much stronger than those across van der Waals gaps, and these differences in coupling between bonded...

The study of the terminal electron transfer system has been approached essentially in two ways. The first approach has been by way of the study of electron transfer in intact cells and in respiratory chain particles such as mitochrondria; it can best be exemplified by the studies of Chance and Williams (1). The second approach, which has been used in this laboratory, involves fragmentation of m...

Ab initio electronic structure calculations on model cations containing a disulfide linkage and a protonated amine site are carried out to examine ow the rate of electron transfer from a Rydberg orbital on the amine site to the S S * orbital depends upon the distance between these two rbitals. These simulations are relevant to both electron-capture and electron-transfer dissociation mass spectr...

The electron accepting properties of the 2,3-dichloro-5,6-dicyanobenzoquinone and iodine and electron donating properties of the drug cilostazole have been studied using the UV-vis, FT-IR, GC-MS and Far-IR techniques. The interaction of cilostazole drug with iodine and 2,3-dichloro-5,6-dicyanobenzoquinone resulted via the initial formation of charge-transfer complex as an intermediate. The rate...

The next generation of nanowires that could advance the integration of functional nanosystems into synthetic applications from photocatalysis to optical devices need to demonstrate increased ability to promote electron transfer at their interfaces while ensuring optimum quantum confinement. Herein we used the biological recognition and the self-assembly properties of tubulin, a protein involved...

The biophysical mechanism of the sense of smell, or olfaction, is still highly debated. The mainstream explanation argues for a shape-based recognition of odorant molecules by olfactory receptors, while recent investigations suggest the primary olfactory event to be triggered by a vibrationally-assisted electron transfer reaction. We consider this controversy by studying the influence of a rece...