University of Basel Researchers Reveal Atomic Switch Controlling Pathogenic Virulence in Leptospira Bacteria

University of Basel researchers uncover the LvrB protein structure, revealing how bacteria trigger infection and offering new paths to treat zoonotic diseases.

By: AXL Media

Published: Apr 28, 2026, 4:28 AM EDT

Source: Information for this report was sourced from EurekAlert!

Decoding the Molecular Machinery of Leptospirosis

The rising prevalence of zoonotic diseases, particularly those influenced by shifting global climates, has placed a spotlight on the pathogenic mechanisms of Leptospira bacteria. According to the research conducted at the University of Basel, this pathogen causes approximately one million severe infections annually, leading to 60,000 deaths. When the bacteria enter a human host, they must undergo a rapid internal transformation to survive the body’s environmental pressures. This transition is governed by a specific protein known as LvrB, which functions as a gatekeeper for the pathogen's ability to cause disease and persist within organ systems.

A Symmetric Lock Guarding Bacterial Inactivity

The structural analysis led by Professor Sebastian Hiller and first author Elia Agustoni has revealed that LvrB remains in a rigid, symmetric state when the bacteria are outside of a host. This "off" position is a critical survival strategy, as it prevents the microorganism from expending energy to produce virulence factors in environments like water or soil where they are not needed. By maintaining this inactive conformation, the bacterium remains effectively harmless until it encounters the specific biological signals indicative of a human or animal host.

The Geometric Shift Triggering Infection

Activation occurs through a complex signaling cascade that initiates once the pathogen detects host-specific triggers. According to Agustoni, chemical modifications to the LvrB protein disrupt its initial symmetry, forcing a structural rearrangement that flips the molecular switch to an active state. Once this conformational change is complete, LvrB interacts with a partner protein to activate hundreds of genes responsible for virulence. This internal genetic mobilization is what allows the bacteria to spread through the body and, if left untreated, eventually cause significant organ failure.