Abstract
Oxidants targeted toward inactivation of the nucleocapsid zinc finger protein are under development as antiviral agents, especially for use against human immunodeficiency virus. In the present study, electrospray ionization-mass spectrometry is used to follow in situ the progress of the reactions of 2,2'-dithiodipyridine and disulfiram with recombinant nucleocapsid protein p7 (Ncp7) from human immunodeficiency virus-1 at pH 7.4. Both reagents react with the two zinc fingers in the protein, resulting in the ejection of two zinc ions and the formation of oxidized apo-Ncp7 with three intramolecular disulfide bonds. The ejection of zinc by 2,2'-dithiodipyridine occurs in two steps. Alkylation of unreacted cysteine residues with N-ethylmaleimide after a 2-min reaction with 2,2'-dithiodipyridine reveals that the carboxyl-terminal zinc finger is disrupted first. Cys-49, Cys-36, and, to a lesser extent, Cys-39 are all shown to be target residues for initial electrophilic attack. In the reaction of disulfiram with Ncp7, ejection of the two zinc ions also occurs in two steps; however, the fully oxidized apo-Ncp7 is formed more rapidly. Thus, after a 40-min reaction, 45% of native Ncp7 is oxidized by 2,2'-dithiodipyridine, whereas 75% is oxidized by disulfiram.
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|