Discipline: Chemistry & Chemical Sciences
Subcategory: STEM Research
Manliang Feng - Tougaloo College
Co-Author(s): Alexandria Morgan, Tougaloo College, Tougaloo MS; Ja'kyra Hicks, Tougaloo College, Tougaloo MS; Jinhe Mao, Tougaloo College, Tougaloo MS; George Armstrong, Tougaloo College, Tougaloo MS
MauG catalyzes the post-translational modification of precursor methylamine dehydrogenase (pre-MADH). This is a 3-step reaction involves the insertion of oxygen on and cross-linking of two tryptophan residues at the active site of the substrate (pre-MADH). The oxidation equivalent is provided by a bis-Fe(IV) species which is formed by the reaction of di-ferric MauG with H2O2. Formation of high valent bis-Fe(IV) species results in a reduction of the Soret band intensity and a formation of a charge-resonance band at 950 nm. In the absence of the pre-MADH the bis-Fe(IV) MauG undergoes auto-reduction to the diferric state. This is a complex multistep reaction involving both proton and electron transfers. The first step is a proton transfer from solvent that generates a Compound I-like state. The second step is a one-electron reduction generates a Compound II-like state. Then another one-electron reduction with loss of water yields the diferric state. Graphene oxides (GO), due to the unique physical and chemical properties have seen growing interest in energy storage, electronics, chemistry and biomedical sciences. In this research we studied the kinetics of the auto-reduction reaction of high valent bis-Fe(IV) MauG on GO. It was found that GO increases the rate constant of the first step of the auto-reduction by almost 10 times, which implies that GO alters the reactions mechanism. The electron donor of the auto-reduction reaction is also likely altered by GO. Electron transfer (ET) reactions are involved in key biological processes, such as oxidative phosphorylation, respiration, photosynthesis as well as many reactions of intermediary metabolism. Therefore the current studies on the electron transfer on GO using MauG as a model could give us insight of how GO affect the electron transfer reaction in the biological processes.
Funder Acknowledgement(s): This research is supported by NSF HBCU UP Implementation project (1912191) and Target Infusion Project (1818528). The authors would also like to thank LS-AMP program for providing student's support.
Faculty Advisor: None Listed,
NSF Affiliation: HBCU-UP