J Biol Chem, Vol. 275, Issue 20, 14890-14897, May 19, 2000
Inactivation of HIV-1 Nucleocapsid Protein P7 by
Pyridinioalkanoyl Thioesters
CHARACTERIZATION OF REACTION PRODUCTS AND PROPOSED MECHANISM OF
ACTION*
Venkatesha
Basrur
,
Yongsheng
Song,
Sharlyn J.
Mazur,
Yuichiro
Higashimoto,
Jim A.
Turpin§,
William G.
Rice¶,
John K.
Inman
, and
Ettore
Appella**
From the Laboratory of Cell Biology, NCI, National
Institutes of Health, Bethesda, Maryland 20892, the
§ Antiviral Research Laboratory, Serquest, Frederick,
Maryland 21702, the ¶ Achillion Pharmaceuticals, Frederick,
Maryland 21701, and the Laboratory of Immunology, NIAID,
National Institutes of Health, Bethesda, Maryland 20892
The synthesis and antiviral properties of
pyridinioalkanoyl thioester (PATE) compounds that target nucleocapsid
p7 protein (NCp7) of the human immunodeficiency virus type 1 (HIV-1)
have been described previously (Turpin, J. A., Song, Y., Inman,
J. K., Huang, M., Wallqvist, A., Maynard, A., Covell, D. G.,
Rice, W. G., and Appella, E. (1999) J. Med. Chem.
42, 67-86). In the present study, fluorescence and electrospray
ionization-mass spectrometry were employed to determine the mechanism
of modification of NCp7 by two lead compounds,
N-[2-(5-pyridiniovaleroylthio)benzoyl]sulfacetamide bromide and
N-[2-(5-pyridiniovaleroylthio)benzoyl]-4-(4-nitrophenylsulfonyl)aniline bromide (compounds 45 and 47, respectively). Although both compounds exhibit antiviral activity in cell-based assays, we failed to detect appreciable ejection of zinc from NCp7 under conditions in which
previously described NCp7-active disulfides readily eject zinc.
However, upon "activation" by Ag+, compound 45 reacted
with NCp7 resulting in the zinc ejection from both zinc fingers. The
reaction followed a two-step mechanism in which zinc was ejected from
the carboxyl-terminal zinc finger faster than from the amino-terminal
zinc finger. Both compounds covalently modified the protein with
pyridinioalkanoyl groups. Compound 45 modified cysteines 36 and 49 of
the carboxyl-terminal zinc finger. The results obtained herein
demonstrate that PATE compounds can be constructed that selectively
target only one of the two zinc fingers of NCp7, thus providing an
impetus to pursue development of highly selective zinc finger inhibitors.
*
This work was supported in part by the Intramural AIDS
Targeted Antiviral Program of the Office of the Director of the
National Institutes of Health to (E. A.).The costs of publication of this article were defrayed in part by the
payment of page charges. The article
must therefore be hereby marked
"advertisement" in accordance with 18 U.S.C. Section
1734 solely to indicate this fact.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
