title: Stoichiometry, selectivity, and exchange dynamics of lipid-protein interaction with bacteriophage M13 coat protein studied by spin label electron spin resonance. Effects of protein secondary structure.
abstract: Bacteriophage M13 major coat protein has been isolated with cholate and reconstituted in dimyristoyl- and dioleoylphosphatidylcholine (DMPC and DOPC, respectively) bilayers by dialysis. Fourier transform infrared spectra of DMPC/coat protein recombinants confirmed that, whereas the protein isolated by phenol extraction was predominantly in a beta-sheet conformation, the cholate-isolated coat protein contained a higher proportion of the alpha-helical conformation [cf. Spruijt, R. B., Wolfs, C. J. A. M., & Hemminga, M. A. (1989) Biochemistry 28, 9158-9165]. The cholate-isolated coat protein/lipid recombinants gave different electron spin resonance (ESR) spectral line shapes of incorporated lipid spin labels, as compared with those from recombinants with the phenol-extracted protein that were studied previously [Wolfs, C. J. A. M., Horváth, L. I., Marsh, D., Watts, A., & Hemminga, M. A. (1989) Biochemistry 28, 9995-10001]. Plots of the ratio of the fluid/motionally restricted components in the ESR spectra of spin-labeled phosphatidylglycerol were linear with respect to the lipid/protein ratio in the recombinants up to 20 mol/mol. The corresponding values of the relative association constants, Kr, and number of association sites, N1, on the protein were Kr approximately 1 and N1 approximately 4 for DMPC recombinants and Kr approximately 1 and N1 approximately 5 for DOPC recombinants. Simulation of the two-component lipid spin label ESR spectra with the exchange-coupled Bloch equations gave values for the off-rate of the lipids leaving the protein surface of 2.0 x 10(7) s-1 at 27 degrees C in DMPC recombinants and 3.0 x 10(7) s-1 at 24 degrees C in DOPC recombinants.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Max-Planck-Institut für biophysikalische Chemie, Abteilung Spektroskopie, Göttingen, Federal Republic of Germany.
authors.forename: S J
authors.initials: SJ
authors.lastname: Peelen
authors.forename: J C
authors.initials: JC
authors.lastname: Sanders
authors.forename: M A
authors.initials: MA
authors.lastname: Hemminga
authors.forename: D
authors.initials: D
authors.lastname: Marsh
mesh_terms: D001435:Bacteriophages / Q000378:metabolism*; D002213:Capsid / Q000378:metabolism*; D004134:Dimyristoylphosphatidylcholine / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D005583:Fourier Analysis; D008051:Lipid Bilayers; D010713:Phosphatidylcholines / Q000378:metabolism; D011487:Protein Conformation; D013055:Spectrophotometry, Infrared
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; C017251:1,2-oleoylphosphatidylcholine; D004134:Dimyristoylphosphatidylcholine