PMID- 27749038
OWN - NLM
STAT- MEDLINE
DCOM- 20170509
LR  - 20170509
IS  - 1520-4995 (Electronic)
IS  - 0006-2960 (Linking)
VI  - 55
IP  - 44
DP  - 2016 Nov 8
TI  - Bifurcation in the Ultrafast Dynamics of the Photoactive Yellow Proteins from 
      Leptospira biflexa and Halorhodospira halophila.
PG  - 6138-6149
AB  - We explored the photoisomerization mechanisms in novel homologues of photoactive 
      yellow protein (PYP) from Leptospira biflexa (Lbif) to identify conserved 
      features and functional diversity in the primary photochemistry of this family of 
      photoreceptors. In close agreement with the prototypical PYP from Halorhodospira 
      halophila (Hhal), we observe excited-state absorbance near 375 nm and stimulated 
      emission near 500 nm, with triphasic excited-state decay. While the excited-state 
      decay for Lbif PYP is the slowest among those of known PYPs due to the 
      redistribution of the amplitudes of the three decay components, the quantum yield 
      for productive photocycle entry is very similar to that of Hhal PYP. Pro68 is 
      highly conserved in PYPs and is important for the high photochemical quantum 
      yield in Hhal PYP, but this residue is Ile in wild-type Lbif PYP. The level of 
      photoproduct formation is slightly increased in I68P Lbif PYP, indicating that 
      this residue regulates the photochemical quantum yield in the entire PYP family. 
      Lbif PYP also exhibited a blue-shifted photoproduct previously undiscovered in 
      ultrafast studies of PYP, which we have named pUV. We posit that pUV is a detour 
      in the PYP photocycle with a twisted protonated pCAH configuration. Cryokinetic 
      experiments with Hhal PYP confirmed the presence of pUV, but the population of 
      this state in room-temperature ultrafast experiments is very small. These results 
      resolve the long-standing inconsistency in the literature regarding the existence 
      of a bifurcation in the room-temperature photocycle of PYP.
FAU - Mix, L Tyler
AU  - Mix LT
AD  - Department of Chemistry, University of California, Davis , One Shields Avenue, 
      Davis, California 95616, United States.
FAU - Kirpich, Julia
AU  - Kirpich J
AD  - Department of Chemistry, University of California, Davis , One Shields Avenue, 
      Davis, California 95616, United States.
FAU - Kumauchi, Masato
AU  - Kumauchi M
AD  - Department of Microbiology and Molecular Genetics, Oklahoma State University , 
      Stillwater, Oklahoma 74078, United States.
FAU - Ren, Jie
AU  - Ren J
AD  - Department of Microbiology and Molecular Genetics, Oklahoma State University , 
      Stillwater, Oklahoma 74078, United States.
FAU - Vengris, Mikas
AU  - Vengris M
AD  - Faculty of Physics, Laser Research Centre, Vilnius University , Sauletekio 10, 
      LT-10233 Vilnius, Lithuania.
FAU - Hoff, Wouter D
AU  - Hoff WD
AD  - Department of Microbiology and Molecular Genetics, Oklahoma State University , 
      Stillwater, Oklahoma 74078, United States.
FAU - Larsen, Delmar S
AU  - Larsen DS
AD  - Department of Chemistry, University of California, Davis , One Shields Avenue, 
      Davis, California 95616, United States.
LA  - eng
PT  - Journal Article
DEP - 20161026
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Bacterial Proteins)
RN  - 0 (Photoreceptors, Microbial)
RN  - 0 (photoactive yellow protein, Bacteria)
SB  - IM
MH  - Bacterial Proteins/*chemistry
MH  - Halorhodospira halophila/*chemistry
MH  - Hydrogen Bonding
MH  - Leptospira/*chemistry
MH  - Photoreceptors, Microbial/*chemistry
MH  - Spectrophotometry, Ultraviolet
EDAT- 2016/10/18 06:00
MHDA- 2017/05/10 06:00
CRDT- 2016/10/18 06:00
PHST- 2016/10/18 06:00 [pubmed]
PHST- 2017/05/10 06:00 [medline]
PHST- 2016/10/18 06:00 [entrez]
AID - 10.1021/acs.biochem.6b00547 [doi]
PST - ppublish
SO  - Biochemistry. 2016 Nov 8;55(44):6138-6149. doi: 10.1021/acs.biochem.6b00547. Epub 
      2016 Oct 26.