Investigating models of protein function and allostery with a widespread mutational analysis of a light-activated protein

Josiah P. Zayner, Chloe Antoniou, Alexander R. French, Ronald J. Hause, Tobin R. Sosnick

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

To investigate the relationship between a protein's sequence and its biophysical properties, we studied the effects of more than 100 mutations in Avena sativa light-oxygen-voltage domain 2, a model protein of the Per-Arnt-Sim family. The A. sativa light-oxygen-voltage domain 2 undergoes a photocycle with a conformational change involving the unfolding of the terminal helices. Whereas selection studies typically search for winners in a large population and fail to characterize many sites, we characterized the biophysical consequences of mutations throughout the protein using NMR, circular dichroism, and ultraviolet/visible spectroscopy. Despite our intention to introduce highly disruptive substitutions, most had modest or no effect on function, and many could even be considered to be more photoactive. Substitutions at evolutionarily conserved sites can have minimal effect, whereas those at nonconserved positions can have large effects, contrary to the view that the effects of mutations, especially at conserved positions, are predictable. Using predictive models, we found that the effects of mutations on biophysical function and allostery reflect a complex mixture of multiple characteristics including location, character, electrostatics, and chemistry.

Original languageEnglish
Pages (from-to)1027-1036
Number of pages10
JournalBiophysical Journal
Volume105
Issue number4
DOIs
Publication statusPublished - 20 Aug 2013

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