PMID: 22080604

Authors:

Harms MJ, Schlessman JL, Sue GR, Garcia-Moreno E B

Title:

Arginine residues at internal positions in a protein are always charged.

Journal:

Proc Natl Acad Sci U S A. 2011 Nov 22;108(47):18954-9. Epub 2011 Nov 11.

Abstract:

Many functionally essential ionizable groups are buried in the hydrophobic interior of proteins. A systematic study of Lys, Asp, and Glu residues at 25 internal positions in staphylococcal nuclease showed that their pK(a) values can be highly anomalous, some shifted by as many as 5.7 pH units relative to normal pK(a) values in water. Here we show that, in contrast, Arg residues at the same internal positions exhibit no detectable shifts in pK(a); they are all charged at pH