The structure of the diheme cytochrome c from Neisseria gonorrhoeae reveals multiple contributors to tuning reduction potentials.

Cytochrome c (c) is a diheme protein implicated as an electron donor to cbb oxidases in multiple pathogenic bacteria. Despite its prevalence, understanding of how specific structural features of c optimize its function is lacking. The human pathogen Neisseria gonorrhoeae (Ng) thrives in low oxygen environments owing to the activity of its cbb oxidase.

Free Thiols Regulate the Interactions and Self-Assembly of Thiol-Passivated Metal Nanoparticles.

Thiol ligands bound to the metallic core of nanoparticles determine their interactions with the environment and self-assembly. Recent studies suggest that equilibrium between bound and free thiols alters the ligand coverage of the core. Here, X-ray scattering and MD simulations investigate water-supported monolayers of gold-core nanoparticles as a function of the core-ligand coverage that is varied in experiments by adjusting the concentration of total thiols (sum of free and bound thiols).

The influence of fractional surface coverage on the core-core separation in ordered monolayers of thiol-ligated Au nanoparticles.

We report the results of grazing incidence X-ray diffraction (GIXD) measurements from water supported Langmuir monolayers of gold nanoparticles ligated with dodecanethiol (12 carbons), tetradecanethiol (14 carbons), hexadecanethiol (16 carbons), and octadecanethiol (18 carbons). These monolayers are formed from solutions with varying concentrations of the respective thiols. We show that equilibrium between adsorbed thiol molecules and the thiols in the bulk solution implies fractional coverage of the Au nanoparticle core.