Fig. 7. Influence of two salt bridges on the regularity of helix composed
of residues 20-33. The first such interation between Glu27 and
Arg30 breaks the helix at Tyr31. The second, the result of interaction
between Arg20 and Asp23, creates a bulge near the N-terminus of
this helical segment.
The above figure is reprinted
by permission from the IUCr:
Acta Crystallogr D Biol Crystallogr