In vivo molecular evolution reveals biophysical origins of organismal fitness

Counago, Rafael, Chen, Stephen and Shamoo, Yousif (2006) In vivo molecular evolution reveals biophysical origins of organismal fitness. Molecular Cell, 22 4: 441-449. doi:10.1016/j.molcel.2006.04.012

Author Counago, Rafael
Chen, Stephen
Shamoo, Yousif
Title In vivo molecular evolution reveals biophysical origins of organismal fitness
Journal name Molecular Cell   Check publisher's open access policy
ISSN 1097-2765
Publication date 2006-05-19
Sub-type Article (original research)
DOI 10.1016/j.molcel.2006.04.012
Volume 22
Issue 4
Start page 441
End page 449
Total pages 9
Place of publication Cambridge, MA, U.S.A.
Publisher Cell Press
Language eng
Abstract In nature, evolution occurs through the continuous adaptation of a population to its environment. At the molecular level, adaptive changes in protein sequence and expression impact organismal fitness and, consequently, dictate population dynamics. Here, we have used a “weak link” method to favor variations in one gene, allowing adaptation to thermostability to be studied in molecular detail as bacteria were grown continuously for ∼1500 generations. Surprisingly, only six mutant alleles, representing less than 1% of the possible missense mutations, were observed, suggesting a highly constrained molecular landscape during protein evolution. The changes in organismal fitness were linked directly to incremental increases in enzyme stability and activity maxima and corresponded to the narrow temperature ranges where each mutant enjoyed success within the overall population. Thus, continuous evolution of a single gene permits a quantitative approach that extends from the phenotypes of the microbial populations to their underlying biophysical basis.
Keyword Escherichia-coli populations
Directed evolution
3-Isopropylmalate dehydrogenase
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
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