[NiFe] hydrogenases are one of the hydrogenase enzymes found in micro-organisms that are capable of producing hydrogen. In this work, we designed a de novo dimeric coiled-coil metallopeptide hydrogenase where two cysteine amino acids are incorporated on each coil to give a tetrathiolate nickel-cysteine catalytic center which mimics the nickel active site of [NiFe] hydrogenase. From circular dichroism and NMR spectroscopy studies, we find that nickel binding to peptide stabilizes the assembly, along with the evidence of characteristic UV-vis electronic transitions of a nickel-thiolate protein. The designed artificial hydrogenase produces hydrogen with a pH-dependent bell-shaped curve where the productivity maximizes at pH 5.6. Fluorescence lifetime and transient absorption spectroscopy techniques are performed to study the pH dependence and the kinetics of electron transfer steps of the photochemical process. The pH titration experiment shows the role of protonated cysteine in determining the pH of maximum photochemical activity. The role of protonated cysteine and the relation between the solution acidity and the electron transfer steps will be discussed in the talk/poster.

Mechanistic insights into photochemical processes of a de novo designed artificial metallopeptide hydrogenase

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.