Poster Presentation International Peptide Symposium 2023

Exploration of the peroxidase-like activity of Cytochrome P450 CYP121 from Mycobacterium tuberculosis (#351)

Hannah Ryan 1 2 , Craig Hutton 1 , David Leys 2
  1. The University of Melbourne, Carlton, VIC, Australia
  2. The University of Manchester, Manchester, England

Cytochrome P450 (CYPs) are a class of oxygenase enzymes often that incorporate a heme group as a cofactor.1 This superfamily of enzymes display some of the greatest substrate range and transformational diversity found in nature. C–C bond formation is a challenging synthetic transformation and a phenomenon observed in only a small subset of P450s species, one of which is CYP121, a cytochrome P450 enzyme from Mycobacterium tuberculosis.2 CYP121 catalyses the dehydrogenative cross-coupling of a cyclo-dityrosine substrate (cYY).3

 

P450 enzymes can drive catalysis via an alternative route than the traditional NADPH/ferredoxin electron transport chain; utilising hydrogen peroxide or organic peracids to generate the iron-oxo heme species that is the precursor to compound I, bypassing the need for external electrons.4

 

CYP121 acts as multifunctional enzyme, performing different substrate-dependent transformations besides C–C cross-linking, such as exhibiting traditional peroxidase activity in some circumstances.  In studies with a range of substrates under different conditions, it has been observed that CYP121 can catalyse a variety of reactions such as hydroxylation and demethylation.

 

Given these interesting alternative products that CYP121 is capable of producing under different conditions, the aim of this project is to help characterise different mechanistic outcomes of reactions catalysed by CYP121. We hope to examine potential of the enzyme to utilise the peroxide shunt utilising solution LC-MS and UV-Vis kinetics experiments as well as time-resolved structural biology techniques to seek to document the reactions at atomic detail.

  1. (1) Munro, A. W.; Girvan, H. M.; Mason, A. E.; Dunford, A. J.; McLean, K. J. What makes a P450 tick? Trends Biochem Sci 2013, 38 (3), 140-150. DOI: 10.1016/j.tibs.2012.11.006 From NLM.
  2. (2) Guengerich, F. P.; Yoshimoto, F. K. Formation and Cleavage of C-C Bonds by Enzymatic Oxidation-Reduction Reactions. Chem Rev 2018, 118 (14), 6573-6655. DOI: 10.1021/acs.chemrev.8b00031 From NLM.
  3. (3) Dornevil, K.; Davis, I.; Fielding, A. J.; Terrell, J. R.; Ma, L.; Liu, A. Cross-linking of dicyclotyrosine by the cytochrome P450 enzyme CYP121 from Mycobacterium tuberculosis proceeds through a catalytic shunt pathway. J Biol Chem 2017, 292 (33), 13645-13657. DOI: 10.1074/jbc.M117.794099 From NLM.
  4. (4) Munro, A. W.; McLean, K. J.; Grant, J. L.; Makris, T. M. Structure and function of the cytochrome P450 peroxygenase enzymes. Biochem Soc Trans 2018, 46 (1), 183-196. DOI: 10.1042/bst20170218 From NLM.