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Atomistic simulation of protein evolution reveals sequence covariation and time-dependent fluctuations of site-specific substitution rates

Norn, Christoffer LU and André, Ingemar LU orcid (2023) In PLoS Computational Biology 19(3 March).
Abstract

Thermodynamic stability is a crucial fitness constraint in protein evolution and is a central factor in shaping the sequence landscapes of proteins. The correlation between stability and molecular fitness depends on the mechanism that relates the biophysical property with biological function. In the simplest case, stability and fitness are related by the amount of folded protein. However, when proteins are toxic in the unfolded state, the fitness function shifts, resulting in higher stability under mutation-selection balance. Likewise, a higher population size results in a similar change in protein stability, as it magnifies the effect of the selection pressure in evolutionary dynamics. This study investigates how such factors affect... (More)

Thermodynamic stability is a crucial fitness constraint in protein evolution and is a central factor in shaping the sequence landscapes of proteins. The correlation between stability and molecular fitness depends on the mechanism that relates the biophysical property with biological function. In the simplest case, stability and fitness are related by the amount of folded protein. However, when proteins are toxic in the unfolded state, the fitness function shifts, resulting in higher stability under mutation-selection balance. Likewise, a higher population size results in a similar change in protein stability, as it magnifies the effect of the selection pressure in evolutionary dynamics. This study investigates how such factors affect the evolution of protein stability, site-specific mutation rates, and residue-residue covariation. To simulate evolutionary trajectories with realistic modeling of protein energetics, we develop an all-atom simulator of protein evolution, RosettaEvolve. By evolving proteins under different fitness functions, we can study how the fitness function affects the distribution of proposed and accepted mutations, site-specific rates, and the prevalence of correlated amino acid substitutions. We demonstrate that fitness pressure affects the proposal distribution of mutational effects, that changes in stability can largely explain variations in site-specific substitution rates in evolutionary trajectories, and that increased fitness pressure results in a stronger covariation signal. Our results give mechanistic insight into the evolutionary consequences of variation in protein stability and provide a basis to rationalize the strong covariation signal observed in natural sequence alignments.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
PLoS Computational Biology
volume
19
issue
3 March
article number
e1010262
publisher
Public Library of Science (PLoS)
external identifiers
  • pmid:36961827
  • scopus:85152005453
ISSN
1553-734X
DOI
10.1371/journal.pcbi.1010262
language
English
LU publication?
yes
id
9fff4a6e-6fb6-4faf-92b9-a93101413aee
date added to LUP
2023-09-22 11:31:01
date last changed
2024-04-19 01:32:06
@article{9fff4a6e-6fb6-4faf-92b9-a93101413aee,
  abstract     = {{<p>Thermodynamic stability is a crucial fitness constraint in protein evolution and is a central factor in shaping the sequence landscapes of proteins. The correlation between stability and molecular fitness depends on the mechanism that relates the biophysical property with biological function. In the simplest case, stability and fitness are related by the amount of folded protein. However, when proteins are toxic in the unfolded state, the fitness function shifts, resulting in higher stability under mutation-selection balance. Likewise, a higher population size results in a similar change in protein stability, as it magnifies the effect of the selection pressure in evolutionary dynamics. This study investigates how such factors affect the evolution of protein stability, site-specific mutation rates, and residue-residue covariation. To simulate evolutionary trajectories with realistic modeling of protein energetics, we develop an all-atom simulator of protein evolution, RosettaEvolve. By evolving proteins under different fitness functions, we can study how the fitness function affects the distribution of proposed and accepted mutations, site-specific rates, and the prevalence of correlated amino acid substitutions. We demonstrate that fitness pressure affects the proposal distribution of mutational effects, that changes in stability can largely explain variations in site-specific substitution rates in evolutionary trajectories, and that increased fitness pressure results in a stronger covariation signal. Our results give mechanistic insight into the evolutionary consequences of variation in protein stability and provide a basis to rationalize the strong covariation signal observed in natural sequence alignments.</p>}},
  author       = {{Norn, Christoffer and André, Ingemar}},
  issn         = {{1553-734X}},
  language     = {{eng}},
  number       = {{3 March}},
  publisher    = {{Public Library of Science (PLoS)}},
  series       = {{PLoS Computational Biology}},
  title        = {{Atomistic simulation of protein evolution reveals sequence covariation and time-dependent fluctuations of site-specific substitution rates}},
  url          = {{http://dx.doi.org/10.1371/journal.pcbi.1010262}},
  doi          = {{10.1371/journal.pcbi.1010262}},
  volume       = {{19}},
  year         = {{2023}},
}