While hydrolysis prone metals like titanium and vanadium have found use in industrial settings in things like solar cells, medical equipment manufacturing, and catalysis, they are underutilized due to their propensity to hydrolyze in unwanted ways. When they are used, it is under harsh, environmentally unfriendly condition that strictly avoid water. Nature has developed metalloenzymes that are able to avoid a metal’s unwanted hydrolysis while still achieving desired enzymatic activity. Using the methods that nature does to stabilize iron (III), we sought to stabilize titanium and vanadium in aqueous solution to expand their potential use to biologically relevant conditions. The <i>de novo </i>designed Due Ferri single chain (DFsc) protein system was developed based on binuclear iron binding sites in natural proteins, and we have recently reported their ability to complex and stabilize Ti against unwanted hydrolytic reactions, allowing the DFsc-Ti complex to carry out reactions under biological conditions. The DFsc system has also shown activity with vanadium and zinc. In order to understand better the features which are most important for stabilizing titanium and vanadium, careful biophysical characterization of a series of DFsc proteins is being undertaken. This characterization includes binding stoichiometry and affinity using circular dichroism (CD) spectroscopy, UV-visible spectroscopy, and inductively coupled plasma – optical emission spectroscopy, and secondary-structural characterization and stability of the protein – metal complex using CD spectroscopy. We have seen differences in the metal binding preferences of some of our proteins depending on the existence of a tyrosine in the active site, indicating that it may be an important interaction in stabilizing titanium and vanadium in the DFsc system.

Biophysical characterization of <i>de novo</i> mini-metalloenzymes

ACS Spring 2022

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

Biophysical characterization of de novo mini-metalloenzymes