Biophysical Spandrels form a Hot-Spot for Kosmotropic Mutations in Bacteriophage Thermal Adaptation
| Autor: | Darin R. Rokyta, A. Carl Whittington |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
0106 biological sciences
Thermotolerance Kosmotropic Hot Temperature Acclimatization Adaptation Biological 010603 evolutionary biology 01 natural sciences Bacteriophage Evolution Molecular 03 medical and health sciences chemistry.chemical_compound Capsid Adaptive mutation Microviridae Genetics Bacteriophages Molecular Biology Ecology Evolution Behavior and Systematics Phylogeny 030304 developmental biology 0303 health sciences biology Base Sequence Protein Stability Temperature Trehalose biology.organism_classification Adaptation Physiological Biological Evolution Metabolic pathway chemistry Osmolyte Mutation Biophysics Capsid Proteins Chemical chaperone |
| Zdroj: | Journal of molecular evolution. 87(1) |
| ISSN: | 1432-1432 |
| Popis: | Temperature plays a dominating role in protein structure and function, and life has evolved myriad strategies to adapt proteins to environmental thermal stress. Cellular systems can utilize kosmotropic osmolytes, the products of complex biochemical pathways, to act as chemical chaperones. These extrinsic molecules, e.g., trehalose, alter local water structure to modulate the strength of the hydrophobic effect and increase protein stability. In contrast, simpler genetic systems must rely on intrinsic mutation to affect protein stability. In naturally occurring microvirid bacteriophages of the subfamily Bullavirinae, capsid stability is randomly distributed across the phylogeny, suggesting it is not phylogenetically linked and could be altered through adaptive mutation. We hypothesized that these phages could utilize an adaptive mechanism that mimics the stabilizing effects of the kosmotrope trehalose through mutation. Kinetic stability of wild-type ID8, a relative of ΦX174, displays a saturable response to trehalose. Thermal adaptation mutations in ID8 improve capsid stability and reduce responsiveness to trehalose suggesting the mutations move stability closer to the kosmotropic saturation point, mimicking the kosmotropic effect of trehalose. These mutations localize to and modulate the hydrophobicity of a cavern formation at the interface of phage coat and spike proteins—an evolutionary spandrel. Across a series of genetically distinct phages, responsiveness to trehalose correlates positively with cavern hydrophobicity suggesting that the level of hydrophobicity of the cavern may provide a biophysical gating mechanism constraining or permitting adaptation in a lineage-specific manner. Our results demonstrate that a single mutation can exploit pre-existing, non-adaptive structural features to mimic the adaptive effects of complex biochemical pathways. |
| Databáze: | OpenAIRE |
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