Structure, Function and Regulation of Antimicrobial and Virulent Amyloids at High-resolution

Introduction

Self-assembly of proteins and peptides into amyloid fibrils produced across kingdoms of life is associated with antimicrobial activity, microbial pathogenicity, and a wide range of diseases. The correlation of fibrillation and morphology to function is poorly understood, and high-resolution structural information and mechanistic models are lacking.

Background

Our lab pioneered the atomic-level analysis of bacterial amyloids and eukaryotic functional fibrils involved in cytotoxicity, biofilm structuring, and antibacterial activity. We revealed novel morphologies extending beyond canonical amyloid cross-β structures of tightly mated β-sheets, to include, for example, cross-α fibrils composed of amphipathic α-helices.

In addition, we exposed a unique lipid-induced cross-α/β secondary structure switch in fibrils of the same sequence.

Objectives

Here we investigate amyloid fibrils which serve as key virulence determinants in S. aureus and Pseudomonas, acting as cytotoxins and in biofilm scaffolding, and as antimicrobials produced across different species.

Methodology

We will leverage the knowledge and expertise, and newly emerging methods in electron, light, and force microscopy, to understand how fibrillation propensity, fibril morphology, and structural switches are connected to function, membrane interactions, and toxicity mechanisms at high resolution.

Expected Outcomes

The findings are expected to identify structural features that underlie the formation, regulation, and activity of these fibrils, providing advantages in specific environments. Understanding these structure-function relationships will help to clarify the link between amyloid formation and antimicrobial activity.

Applications

We will use the insights gained from these studies for the rational design of antimicrobial peptides and small molecules targeting virulent determinants towards potential applications in the management of infectious diseases.

Broader Impact

Our findings on functional amyloids can overall advance life, material, medical, and environmental sciences.