Glycyl radical activating enzymes: structure, mechanism, and substrate interactions

Area of Science:

• Biochemistry
• Enzymology
• Protein Chemistry

Background:

• Glycyl radical enzyme activating enzymes (GRE-AEs) are part of the radical S-adenosylmethionine (SAM) superfamily.
• GRE-AEs utilize a [4Fe-4S] cluster and SAM to catalyze H-atom abstraction, activating substrate proteins known as glycyl radical enzymes (GREs).
• Activated GREs subsequently catalyze diverse biochemical reactions via substrate radical intermediates.

Purpose of the Study:

• To review research on the extensively characterized pyruvate formate lyase activating enzyme (PFL-AE).
• To provide insights into the active site structure and substrate interactions of GRE-AEs.
• To discuss other GREs and their corresponding activating enzymes.

Main Methods:

• Literature review focusing on PFL-AE.
• Analysis of structural and mechanistic studies of radical SAM enzymes.
• Comparative discussion of various GRE-AE/GRE systems.

Main Results:

• PFL-AE serves as a model for understanding GRE-AE structure and function.
• Detailed insights into the interactions between GRE-AEs, their GRE substrates, and external electron donors.
• Highlights the diversity of reactions catalyzed by GREs following activation.

Conclusions:

• PFL-AE provides a foundational understanding of the GRE-AE family.
• GRE-AEs are crucial for activating a diverse set of enzymes involved in various metabolic pathways.
• Further research on GRE-AEs and GREs will illuminate complex radical-based biological processes.