Modelling quantitative structure-activity relationships between animal behaviour and environmental signal molecules

Area of Science:

• Marine Biology
• Chemical Ecology
• Biophysics

Background:

• Environmental signal molecules, specifically small peptides, are known to stimulate larval settlement in oysters and barnacles, and abdominal pumping for dispersal in mud crabs.
• Previous studies identified arginine or lysine at the carboxy terminus of active peptides, with variable preceding amino acids.

Purpose of the Study:

• To establish quantitative structure-activity relationships (QSARs) linking physicochemical properties of environmental signal molecules to animal behavior.
• To explain the variability in amino acid sequences that elicit behavioral responses and hypothesize more potent peptide analogues.

Main Methods:

• Utilized the multivariate partial least squares algorithm to correlate composite amino acid properties (hydrophilicity, size, charge) and sequence position with behavioral patterns.
• Applied QSAR models to analyze oyster, barnacle, and mud crab responses to peptide cues.

Main Results:

• QSAR models successfully explained the variability in amino acid sequences responsible for behavioral responses in oysters, barnacles, and mud crabs.
• Identified structural similarities between these environmental peptide signals and mammalian C5a anaphylatoxin.
• Demonstrated that QSAR models can differentiate optimal peptide sequences for distinct species-specific behaviors.

Conclusions:

• QSARs offer a powerful approach to relate molecular physicochemical properties to animal behavior.
• These models can differentiate species-specific responses to chemical signals, even when species share habitats.
• The findings highlight the potential for designing novel peptide analogues with enhanced activity.