Plastocyanin (PC) is a 10.5 kD blue copper protein which functions in chloroplast electron transfer. A chemical modification approach will be used to study binding sites, conformational changes and electrostatic effects in PC. A series of carboxyl modified PC's has been prepared which contains molecules of ethylenediamine at specific locations. A series of amino modified PC's will also be prepared. These will be used to study the interaction of PC with its physiological reaction partners (cytochrome f and P700) in order to determine where they bind on the PC molecule. The effect of modification on the reactions of PC with negatively and positively charged artificial electron donors and acceptors will be studied in order to determine the effect of changing the charge on PC at one location on reactions occurring at another. Effects on the midpoint redox potential and its pH dependence will also be determined. NearUV CD and flourescence will be used to determine whether modification causes conformational changes in PC. NMR will be used to determine whether modification affects thee ligands to the copper in reduced PC. A cyt f PC adduct (Davis and Hough, 1983) will be made in order to determine whether adduct formation alters the redox potential of PC. The results of this study will increase our knowledge of electron transport mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
1R01GM038300-01
Application #
3294611
Study Section
Biophysics and Biophysical Chemistry A Study Section (BBCA)
Project Start
1987-04-01
Project End
1990-03-31
Budget Start
1987-04-01
Budget End
1988-03-31
Support Year
1
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Ohio State University
Department
Type
Schools of Arts and Sciences
DUNS #
098987217
City
Columbus
State
OH
Country
United States
Zip Code
43210
Durell, S R; Labanowski, J K; Gross, E L (1990) Modeling of the electrostatic potential field of plastocyanin. Arch Biochem Biophys 277:241-54
Durell, S R; Lee, C H; Ross, R T et al. (1990) Factor analysis of the near-ultraviolet absorption spectrum of plastocyanin using bilinear, trilinear, and quadrilinear models. Arch Biochem Biophys 278:148-60
Durell, S R; Gross, E L; Draheim, J E (1988) Analysis of the near-ultraviolet absorption and circular dichroic spectra of parsley plastocyanin for the effects of pH and copper center conformation changes. Arch Biochem Biophys 267:217-27