# The Bacteriophage VMY 22 Has Enhanced the Stability of Its Functional Proteins via Adaptive Evolution in a Temperature-Varying Environment

## TL;DR

This study shows how a glacier bacteriophage adapts to temperature changes by evolving its functional proteins, improving stability in varying environments.

## Contribution

The paper reveals a novel mechanism of temperature-driven functional protein evolution in cold-adapted bacteriophages.

## Key findings

- Phage VMY22 showed temperature-dependent infectivity changes and genomic mutations in functional genes.
- Protein structural adaptations were observed in response to different environmental temperatures.
- Functional gene mutations suggest evolution primarily affects post-adsorption processes in phage.

## Abstract

Temperature fluctuations strongly affect microbial viability, often inducing adaptive responses. In this study, we employed the psychrophilic bacterium Bacillus mycoides 41-22 and its associated phage VMY22, originally isolated from the Mingyong Glacier, to investigate phage adaptability under varied temperature conditions. Through selective enrichment at 4 °C, 15 °C, 28 °C, and 32 °C, we observed clear differences in phage infectivity, as assessed by plaque assays, along with genomic mutations and protein structural changes. Notably, mutations predominantly occurred in functional genes (ATPase, endolysin), while the examined structural loci remained conserved. Homology modeling revealed distinct adaptations in protein tertiary structures corresponding to environmental temperatures, suggesting that phage evolution mainly affects post-adsorption processes. Our findings elucidate a novel mechanism of temperature-driven functional protein evolution among cold-adapted bacteriophages (phage) and providing insights into their potential applications in microbial ecology and biotechnology.