CONFORMATIONAL STABILITY OF THE ENDOTHELIN SARAFOTOXIN FAMILY OF PEPTIDES/

There are significant differences between the structures reported for members of the endothelin/sarafotoxin family of peptides, but also for the same peptides studied by different groups, raising the possibilit y that some of the differences are attributable to variation in soluti on conditions rather than intrinsic structural heterogeneity. We have shown, using circular dichroism spectroscopy and equilibrium sedimenta tion, that the secondary structures of these peptides are little affec ted by wide variations in pH, or by self-association. Although acetoni trile has a pronounced effect on the extent of peptide self-associatio n it does not appear to alter the backbone structure of sarafotoxin SR Tb, and has only minor effects on endothelin-l and endothelin-3. The o bserved conformational variation thus appears largely to reflect seque nce-dependent differences. (C) Munksgaard 1994.