Download MendeleyA Ferric-Superoxide Intermediate Initiates P450-Catalyzed Cyclic Dipeptide Dimerization.
Gering, H.E., Li, X., Tang, H., Swartz, P.D., Chang, W.C., Makris, T.M.(2023) J Am Chem Soc 145: 19256-19264
- PubMed: 37611404
- DOI: https://doi.org/10.1021/jacs.3c04542
- Primary Citation of Related Structures:
8TWU - PubMed Abstract:
The cytochrome P450 (CYP) AspB is involved in the biosynthesis of the diketopiperazine (DKP) aspergilazine A. Tryptophan-linked dimeric DKP alkaloids are a large family of natural products that are found in numerous species and exhibit broad and often potent bioactivity. The proposed mechanisms for C-N bond formation by AspB, and similar C-C bond formations by related CYPs, have invoked the use of a ferryl-intermediate as an oxidant to promote substrate dimerization. Here, the parallel application of steady-state and transient kinetic approaches reveals a very different mechanism that involves a ferric-superoxide species as a primary oxidant to initiate DKP-assembly. Single turnover kinetic isotope effects and a substrate analog suggest the probable nature and site for abstraction. The direct observation of CYP-superoxide reactivity rationalizes the atypical outcome of AspB and reveals a new reaction manifold in heme enzymes.
Organizational Affiliation:
Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695, United States.
