Key points are not available for this paper at this time.
HPr is a small protein that must unfold to translocate the α-hemolysin pore (see image). Single amino acid substitutions can cause large changes to the translocation parameters. A conservative mutation is sufficient to alter the event profile; either the mutant must unfold differently or it must interact with the pore differently. A negatively charged mutant is driven through the pore, which facilitates unfolding.
Stefureac et al. (Mon,) studied this question.