Structural Insights into CYP450 enzymes

Enzymes are proteins that exist in all living things to accelerate (catalyse) chemical reactions, thus speeding up complex biological processes. Enzymes are involved in a wide variety of biological functions, including digesting food or making copies of DNA. There are many enzymes in nature; specific enzymes work to catalyse the cleavage of chemical bonds and there are also enzymes that work to catalyse the formation of chemical bonds.  

 Cytochrome P450s (CYP450s) belong to a group of enzymes that specifically use the oxygen molecule to metabolize complex molecules. For example, humans have CYP450s to metabolize drugs and external substances. Researchers who have studied ribosomal and non-ribosomal biosynthesis have identified CYP450s as vital enzymes in the catalysis of sidechain cross-linking chemical reactions — these are reactions in molecules containing two (or more) reactive ends capable of being chemically linked to one another. Since then, various investigations have pursued the study of these CYP450 enzymes and their biological significance in making new chemical bonds. Engineering enzymes to make new chemical bonds is a highly sought-after goal in peptide and protein science because it offers researchers access to new resources – biocatalysts – to generate unique cyclic peptides. Centre Investigators Professor Max Cryle and Professor Colin Jackson, Associate Investigators Dr Max Crüsemann and Professor James De Voss, CIPPS Research Fellows Dr Mathias Hansen and Dr Julien Tailhades along with PhD students Vishnu Mini Sasi and CIPPS Alumni Dr Yongwei Zhao have used computational and biochemical techniques to reveal the structure of a biarylitide cross-linking CYP450 enzyme, P450Blt, and in doing so have helped us to understand how this enzyme can make unique linkages in cyclic peptides.  

Through their cross-nodal collaboration they successfully characterized a biarylitide cross-linking P450 in complex with a peptide molecule. This allowed them to identify that the structure of the central I-helix in these P450 enzymes is central to differences in the bioactivities of these types of enzymes. As an example, residues in this I-helix were found to be vital in coordinating with the incoming histidine residue of the peptide substrate and were fundamental to how the enzyme controls the new chemical bonds it generates. This new understanding contributes to the potential of a new toolkit to generate unique cyclic peptides, which are otherwise difficult to synthesise using chemistry alone. 

 Citation: Hansen, Mathias H., Angus Keto, Maxine Treisman, Vishnu Mini Sasi, Laura Coe, Yongwei Zhao, Leo Padva et al. Structural Insights into a Side Chain Cross-Linking Biarylitide P450 from RiPP Biosynthesis. ACS Catal. 2024, 812 

 Doi: 10.1021/acscatal.3c05417 

 CIPPS contributors: Max Cryle, Colin Jackson, Max Crüsemann, James De Voss, Mathias Hansen, Julien Tailhades, Maxine Treisman, Vishnu Mini Sasi, Yongwei Zhao, Daniel Machell.