INFLUENCE OF LONG-RANGE INTERACTIONS ON STRUCTURE OF MYOGLOBIN

The optical rotatory dispersion and circular dichroism of the three isolated cyanogen bromide peptides of apomyoglobin have been examined. From these data, it appears that the helix contents of the peptides in water are markedly lower than they are in the parent protein, although these peptides do assume conformations of higher helix content in 95% aqueous methanol. Sedimentation studies indicate that the N-terminal peptide is aggregated in water, but the other two are not. The results for the two unaggregated peptides suggest that long-range interhelical interactions may play an important role in determining protein conformation. In addition, there may be a connection between the tendency of the N-terminal peptide to aggregate and its possible role in initiating protein folding. © 1968, American Chemical Society. All rights reserved.