Mismatched ions indicate quantum effects in proteins

L. Ridgway Scott; Ariel Fernandez Stigliano. 8 November, 2015.
Communicated by L. Ridgway Scott.


We present a large number of examples of sidechain interactions in which it appears at first that highly unfavorable positive charges are in close proximity. In particular, we examine pairs of arginines (resp., lysines) whose sidechain CZ (resp., NZ) atoms are very close. We screen PDB files to find such pairs for which there are no plausible counter ions. On the other hand, we show that invariably there are dehydrons in the vicinity of the like-charge pairs that can promote deprotonation of positively charged sidechains, eliminating the charge mismatch. The chemical functionality of dehydrons is articulated through the co-option of nearby water molecules which are turned into proton acceptors (chemical base). This provides a plausible explanation for the unusual motif.

Original Document

The original document is available in PDF (uploaded 8 November, 2015 by L. Ridgway Scott).