title: FTIR Spectroscopy Revealing Light-Dependent Refolding of the Conserved Tongue Region of Bacteriophytochrome.
abstract: Bacteriophytochromes (BphPs) constitute a class of photosensory proteins that toggle between Pr and Pfr functional states through absorption of red and far-red light. The photosensory core of BphPs is composed of PAS, GAF, and PHY domains. Here, we apply FTIR spectroscopy to investigate changes in the secondary structure ofRhodopseudomonas palustrisBphP2 (RpBphP2) upon Pr to Pfr photoconversion. Our results indicate conversion from a β-sheet to an α-helical element in the so-called tongue region of the PHY domain, consistent with recent X-ray structures ofDeinococcus radioduransDrBphP in dark and light states (Takala H.; et al. Nature2014, 5, 245-248). A conserved Asp in the GAF domain that noncovalently connects with the PHY domain and a conserved Pro in the tongue region of the PHY domain are essential for the β-sheet-to-α-helix conversion.
authors.affiliation: Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Emina A
authors.initials: EA
authors.lastname: Stojković
authors.affiliation: Department of Physics, VU University , De Boelelaan 1081, 1081HV Amsterdam, The Netherlands.
authors.forename: K C
authors.initials: KC
authors.lastname: Toh
authors.affiliation: Department of Physics, VU University , De Boelelaan 1081, 1081HV Amsterdam, The Netherlands.
authors.forename: Maxime T A
authors.initials: MT
authors.lastname: Alexandre
authors.affiliation: Department of Physics, VU University , De Boelelaan 1081, 1081HV Amsterdam, The Netherlands.
authors.forename: Marian
authors.initials: M
authors.lastname: Baclayon
authors.affiliation: Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States ; Department of Biochemistry and Molecular Biology and Institute for Biophysical Dynamics, The University of Chicago , Chicago, Illinois 60637, United States.
authors.forename: Keith
authors.initials: K
authors.lastname: Moffat
authors.affiliation: Department of Physics, VU University , De Boelelaan 1081, 1081HV Amsterdam, The Netherlands.
authors.forename: John T M
authors.initials: JT
authors.lastname: Kennis