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Updated: Jul 5, 2026

Amide Hydrogen/Deuterium Exchange & MALDI-TOF Mass Spectrometry Analysis of Pak2 Activation
Published on: November 26, 2011
Partitioning the loss in vancomycin binding affinity for D-Ala-D-Lac into lost H-bond and repulsive lone pair
Casey C McComas1, Brendan M Crowley, Dale L Boger
1Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Abstract:
The binding affinity of 4, which incorporates a methylene (CH2) in place of the key linking amide of Ac2-l-Lys-d-Ala-d-Ala, for vancomycin was compared with that of Ac2-l-Lys-d-Ala-d-Ala (3) and Ac2-l-Lys-d-Ala-d-Lac (5). The vancomycin affinity for 4 was approximately 10-fold less than that of 3, but 100-fold greater than that of 5. This suggests that the reduced binding affinity of 5 (4.1 kcal/mol) may be attributed to both the loss of a key H-bond (1.5 kcal/mol) and a destabilizing lone pair/lone pair electrostatic interaction introduced with the ester oxygen of 5 (2.6 kcal/mol) with the latter, not the H-bond, being responsible for the largest share of the 1000-fold reduction.
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