Ionization state of the catalytic dyad Asp25/25′ in the HIV-1 protease: NMR studies of site-specifically 13C labelled HIV-1 protease prepared by total chemical synthesis

Abstract

Total chemical synthesis was used to site-specifically ¹³C-label active site Asp25 and Asp25′ residues in HIV-1 protease and in several chemically synthesized analogues of the enzyme molecule. ¹³C NMR measurements were consistent with a monoprotonated state for the catalytic dyad formed by the interacting Asp25, Asp25′ side chain carboxyls.