Figure 2

Inter-relationship between φψ and φχ1 plots. A set of pentapeptides with pro at position 3 were displayed using the ‘φψχ’ combination setting (Figure1) and selections made in the χ1 region of position 3 corresponding to (a) the DOWN pucker, and (b) the UP pucker of the pro ring. Only the plots for positions 2 and 3 are shown. Note that the y axis (χ) of the φχ1 portion of the φψχ plot defaults to the range –120˚ to 240˚ to prevent the trans rotamer being split across the 180˚/–180˚ boundary.