Allosterism in the PDZ Family

Area of Science:

• Biochemistry and Molecular Biology
• Structural Biology
• Protein Dynamics

Background:

• Dynamic allostery is crucial for signal propagation within proteins.
• The PDZ (PSD-95/Dlg1/ZO-1) domain family serves as a model for studying allostery in small modular protein domains.
• Previous research has concentrated on a limited number of PDZ domains, such as PTP-BL PDZ2, PSD-95 PDZ3, and Par6 PDZ.

Purpose of the Study:

• To review and consolidate identified residues involved in dynamic allostery within specific PDZ domains.
• To serve as a reference index for allosteric sites within the PDZ protein family.
• To investigate evolutionary conservation patterns of allosteric residues across different PDZ domains.

Main Methods:

• Compilation and summary of experimental and computational studies identifying allosteric residues.
• Comparative analysis of residue conservation across PTP-BL PDZ2 and PSD-95 PDZ3 domains.
• Identification of specific residues on the αA helix, αB lower-loop, and αC helix implicated in allostery.

Main Results:

• Specific residues on the αA helix, αB lower-loop, and αC helix are consistently involved in dynamic allostery across studied PDZ domains.
• Despite low sequence identity within the PDZ family, conserved allosteric residues (A46/A347, V61/V362, L66/L367) were identified in PTP-BL PDZ2 and PSD-95 PDZ3.
• The findings reveal conserved allosteric mechanisms within the PDZ domain family.

Conclusions:

• Dynamic allostery is a conserved feature in the PDZ domain family, with specific residues playing key roles.
• Evolutionary conservation of allosteric residues suggests functional importance.
• Future research should focus on PDZ domains with diverse binding partners and multidomain constructs to further elucidate allosteric mechanisms.