Photoactive yellow protein (PYP) is the prototype for a large family of proteins containing a structural motif referred to as the PAS domain. PAS domains function in a variety of signaling and regulatory roles in eucaryotes as well as procaryotes. Photoactive yellow protein (PYP) is a small soluble protein which appears to have a variety of signaling roles in purple bacteria. The goals of the proposed studies are four fold. 1. To elucidate the chemical and structural characteristics of the photocycle intermediates. 2.To understand the role of specific amino acid side chains in the kinetic and spectral properties of the ground state and intermediates. 3. To establish the mechanism(s) by which PYP signals to its reaction partners and utilizes the photocycle to function in vivo. 4. To establish the differences, in both functional and physico-chemical properties, among the three types of PYP identified to date. Structural, thermodynamic, kinetic and optical properties of the wild-type, site-specific mutants and variant chromophores will be studied. A variety of techniques will be utilized, including x-ray crystallography, NMR, UV/VIS spectroscopy, kinetic measurements in time domains ranging from femtoseconds to seconds, picosecond Coherent Anti-Stokes Raman Spectroscopy (CARS), picosecond time resolved CARS, and computer modeling.The significance of the proposed work is three fold. First, PYP will provide key insights which will help elucidate the role of PAS domains in signaling and regulation. This information will contribute directly to a better understanding of all of the members of the PAS domain family. Second, PYP offers the opportunity to understand the key elements in photoactive proteins - the spectral red-shift of the ground state protein and of key intermediates, how photoisomerization can be used to drive function, and the structure of photocycle intermediates. This level of understanding will complement work with membrane-bound photoactive proteins (bacteriorhodopsin, sensory rhodopsin and rhodopsin) and will provide information not available with these systems. Third, it is possible that an understanding of PYP and photoactive proteins in general will contribute to the development of photobioelectronic switching devices which will have applications in the next generation of small, fast, low power electronics

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM066146-01
Application #
6531991
Study Section
Physical Biochemistry Study Section (PB)
Program Officer
Ikeda, Richard A
Project Start
2002-08-01
Project End
2005-07-31
Budget Start
2002-08-01
Budget End
2003-07-31
Support Year
1
Fiscal Year
2002
Total Cost
$255,559
Indirect Cost
Name
University of Arizona
Department
Biochemistry
Type
Schools of Arts and Sciences
DUNS #
City
Tucson
State
AZ
Country
United States
Zip Code
85721
Hoersch, Daniel; Otto, Harald; Cusanovich, Michael A et al. (2009) Time-resolved spectroscopy of dye-labeled photoactive yellow protein suggests a pathway of light-induced structural changes in the N-terminal cap. Phys Chem Chem Phys 11:5437-44
Hoersch, Daniel; Otto, Harald; Cusanovich, Michael A et al. (2008) Distinguishing chromophore structures of photocycle intermediates of the photoreceptor PYP by transient fluorescence and energy transfer. J Phys Chem B 112:9118-25
Kyndt, John A; Savvides, Savvas N; Memmi, Samy et al. (2007) Structural role of tyrosine 98 in photoactive yellow protein: effects on fluorescence, gateway, and photocycle recovery. Biochemistry 46:95-105
Borucki, Berthold; Joshi, Chandra P; Otto, Harald et al. (2006) The transient accumulation of the signaling state of photoactive yellow protein is controlled by the external pH. Biophys J 91:2991-3001
Joshi, Chandra P; Borucki, Berthold; Otto, Harald et al. (2006) Photocycle and photoreversal of photoactive yellow protein at alkaline pH: kinetics, intermediates, and equilibria. Biochemistry 45:7057-68
Borucki, Berthold; Otto, Harald; Meyer, Terrance E et al. (2005) Sensitive circular dichroism marker for the chromophore environment of photoactive yellow protein: assignment of the 307 and 318 nm bands to the n --> pi* transition of the carbonyl. J Phys Chem B 109:629-33
Borucki, Berthold; Kyndt, John A; Joshi, Chandra P et al. (2005) Effect of salt and pH on the activation of photoactive yellow protein and gateway mutants Y98Q and Y98F. Biochemistry 44:13650-63
Otto, Harald; Hoersch, Daniel; Meyer, Terry E et al. (2005) Time-resolved single tryptophan fluorescence in photoactive yellow protein monitors changes in the chromophore structure during the photocycle via energy transfer. Biochemistry 44:16804-16
Heyne, Karsten; Mohammed, Omar F; Usman, Anwar et al. (2005) Structural evolution of the chromophore in the primary stages of trans/cis isomerization in photoactive yellow protein. J Am Chem Soc 127:18100-6
Kyndt, John A; Fitch, John C; Meyer, Terry E et al. (2005) Thermochromatium tepidum photoactive yellow protein/bacteriophytochrome/diguanylate cyclase: characterization of the PYP domain. Biochemistry 44:4755-64

Showing the most recent 10 out of 16 publications