Phosphoryl group transfer: evolution of a catalytic scaffold

Area of Science:

• Biochemistry and Molecular Biology
• Enzymology
• Evolutionary Biology

Background:

• Enzymic phosphoryl-transfer reactions are fundamental to numerous biological processes.
• These reactions can proceed through various proposed mechanisms, including concerted, associative (phosphorane-intermediate), and dissociative (metaphosphate-intermediate) pathways.
• The specific mechanism is influenced by the enzyme's catalytic scaffold and the nature of the reactants.

Purpose of the Study:

• To explore the mechanistic diversity of phosphoryl-transfer reactions within enzyme families.
• To investigate the evolutionary dynamics of these mechanisms in response to changing substrates.
• To describe the phosphotransferases of the haloacid dehalogenase superfamily in the context of catalytic scaffold and mechanism co-evolution.

Main Methods:

• Analysis of proposed reaction mechanisms for phosphoryl-transfer enzymes.
• Examination of evolutionary trends in phosphotransferase families.
• Characterization of the haloacid dehalogenase superfamily's enzymes and their catalytic mechanisms.

Main Results:

• Enzymic phosphoryl-transfer mechanisms are proposed to be flexible, adapting to different catalytic scaffolds and reactants.
• The mechanism of phosphoryl-transfer reactions is not static during the evolution of a phosphotransferase family, undergoing potential changes with scaffold adaptations.
• The haloacid dehalogenase superfamily, a large and widespread group, showcases this co-evolution of catalytic scaffold and reaction mechanism.

Conclusions:

• Enzyme mechanisms, particularly phosphoryl-transfer, are subject to evolutionary flux.
• The catalytic scaffold plays a crucial role in dictating the reaction mechanism.
• The haloacid dehalogenase superfamily serves as a key model for understanding the interplay between enzyme evolution, scaffold adaptation, and mechanistic diversification.