INTERACTION OF 2 COMPLEMENTARY FRAGMENTS OF THE BOVINE SPINAL-CORD MYELIN BASIC-PROTEIN WITH PHOSPHATIDYLGLYCEROL BILAYERS, STUDIED BY H-2 AND P-31 NMR-SPECTROSCOPY
M. Hayerhartl et al., INTERACTION OF 2 COMPLEMENTARY FRAGMENTS OF THE BOVINE SPINAL-CORD MYELIN BASIC-PROTEIN WITH PHOSPHATIDYLGLYCEROL BILAYERS, STUDIED BY H-2 AND P-31 NMR-SPECTROSCOPY, Biochemistry, 32(37), 1993, pp. 9709-9713
The interaction of two complementary fragments of myelin basic protein
from bovine spinal cord with bilayers of dimyristoylphosphatidylglyce
rol has been studied by broad line H-2 and P-31 NMR. The fragments, pr
oduced by cleavage at the single tryptophan, consist of an N-terminal
portion of molecular mass 12.6 kDa and a C-terminal portion of molecul
ar mass 5.8 kDa. The phosphatidylglycerol lipid was deuterated at all
three segments of the glycerol headgroup. The approximately linear dep
endence of the H-2 quadrupole splittings and P-31 chemical shift aniso
tropy on protein/lipid ratio in the complexes indicates that the lipid
s interacting with the protein fragments were in fast exchange on the
NMR time scale (almost-equal-to 10(-4)-10(-5) s). The relative gradien
ts of the dependence on protein/lipid ratio of both these parameters d
ecrease with the size of the protein fragment and correlate reasonably
well with both the net charge on the protein and the lipid binding st
oichiometries in the absence of salt. The results are therefore consis
tent with a model in which the perturbation of the quadrupole splittin
gs either is determined by the net surface potential or is constant fo
r the different protein fragments. Either possibility is consistent wi
th the reduced activity of the fragments relative to the whole protein
.