Premium
Picometer‐scale conformational heterogeneity separates functional from non‐functional states of a photoreceptor protein
Author(s) -
Genick Ulrich Karl,
Coureux Pierre Damien,
Fan Zi Peng,
Stojanoff Vivian
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a638
Subject(s) - molecule , chemistry , population , crystal structure , homogeneous , biophysics , crystallography , physics , biology , organic chemistry , sociology , thermodynamics , demography
We combined ultra‐high resolution X‐ray crystallography, cryogenic trapping and in‐crystal photoactivation to show that subtle picometer‐scale variations in protein structure have dramatic effects on the function of the bacterial photoreceptor PYP. Specifically we show that what appears to be a homogeneous structural population – even in a 0.82Å crystal structure – is in fact a mix of highly active and inactive molecular states. Of particular note is that the light‐sensing activity of the overall photoreceptor population is wholly attributable to a minor conformational substate, while the dominant structural state is inactive. Interestingly, the molecules that show photo activity are those, in which the displacement of active‐site atoms anticipate the trajectory of the photoactivation reaction. Further, our results indicate that the molecule‐to‐molecule functional heterogeneity observed in a series of recent single‐molecule experiments may be caused by structural differences that are too sublte to be observed by standard structure determination techniques.