Experimental evolution of adenylate kinase reveals contrasting strategies toward protein thermostability

Miller, Corwin, Davlieva, Milya, Wilson, Corey, White, Kristopher I., Counago, Rafael, Wu, Gang, Myers, Jeffrey C., Wittung-Stafshede, Pernilla and Shamoo, Yousif (2010) Experimental evolution of adenylate kinase reveals contrasting strategies toward protein thermostability. Biophysical Journal, 99 3: 887-896. doi:10.1016/j.bpj.2010.04.076

Author Miller, Corwin
Davlieva, Milya
Wilson, Corey
White, Kristopher I.
Counago, Rafael
Wu, Gang
Myers, Jeffrey C.
Wittung-Stafshede, Pernilla
Shamoo, Yousif
Title Experimental evolution of adenylate kinase reveals contrasting strategies toward protein thermostability
Journal name Biophysical Journal   Check publisher's open access policy
ISSN 0006-3495
Publication date 2010-08-04
Sub-type Article (original research)
DOI 10.1016/j.bpj.2010.04.076
Volume 99
Issue 3
Start page 887
End page 896
Total pages 10
Place of publication St. Louis, MO, United States
Publisher Cell Press
Language eng
Formatted abstract
Success in evolution depends critically upon the ability of organisms to adapt, a property that is also true for the proteins that contribute to the fitness of an organism. Successful protein evolution is enhanced by mutational pathways that generate a wide range of physicochemical mechanisms to adaptation. In an earlier study, we used a weak-link method to favor changes to an essential but maladapted protein, adenylate kinase (AK), within a microbial population. Six AK mutants (a single mutant followed by five double mutants) had success within the population, revealing a diverse range of adaptive strategies that included changes in nonpolar packing, protein folding dynamics, and formation of new hydrogen bonds and electrostatic networks. The first mutation, AKBSUB Q199R, was essential in defining the structural context that facilitated subsequent mutations as revealed by a considerable mutational epistasis and, in one case, a very strong dependence upon the order of mutations. Namely, whereas the single mutation AKBSUB G213E decreases protein stability by >25°C, the same mutation in the background of AKBSUB Q199R increases stability by 3.4°C, demonstrating that the order of mutations can play a critical role in favoring particular molecular pathways to adaptation. In turn, protein folding kinetics shows that four of the five AKBSUB double mutants utilize a strategy in which an increase in the folding rate accompanied by a decrease in the unfolding rate results in additional stability. However, one mutant exhibited a dramatic increase in the folding relative to a modest increase in the unfolding rate, suggesting a different adaptive strategy for thermostability. In all cases, an increase in the folding rates for the double mutants appears to be the preferred mechanism in conferring additional stability and may be an important aspect of protein evolution. The range of overlapping as well as contrasting strategies for success illustrates both the power and subtlety of adaptation at even the smallest unit of change, a single amino acid.
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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