J Biol Chem, Vol. 274, Issue 3, 1549-1556, January 15, 1999
The Connection Domain Is Implicated in Metalloporphyrin Binding
and Inhibition of HIV Reverse Transcriptase
Elias G.
Argyris
§,
Jane M.
Vanderkooi§¶,
P. S.
Venkateswaran
,
Brian K.
Kay**, and
Yvonne
Paterson
§
From the Departments of
Microbiology and
¶ Biochemistry and Biophysics and the § Johnson
Research Foundation, University of Pennsylvania School of Medicine and
the
Institute for Antiviral Research, University City Science
Center, Philadelphia, Pennsylvania 19104 and the ** Department of
Pharmacology, University of Wisconsin,
Madison, Wisconsin 53706-1532
We have shown that heme and zinc protoporphyrin
inhibit both human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) reverse transcriptases (RTs) and, in combination with other
nucleoside and non-nucleoside inhibitors, exert an additive effect on
HIV-1 RT inhibition. Screening of a phage peptide library against heme resulted in the isolation of a peptide with sequence similarity to
sequence 398-407 from the connection subdomain of both HIV-1 and HIV-2
RTs, suggesting that this highly conserved region of HIV RTs
corresponds to the binding site for metalloporphyrins and a new site
for inhibition of enzyme activity. Inclusion of a synthetic peptide
corresponding to the exact sequence 398-407 of HIV-1 RT in RT
inhibition assays had a protective effect on metalloporphyrin
inhibition, as it was able to reverse the inhibitory effect of both
metalloporphyrins on HIV-1 RT activity. Furthermore, intrinsic
fluorescence assays indicated that these metalloporphyrins bind to
synthetic peptide 398-407 as well as to intact dimeric HIV-1 RT. The
identification of this novel inhibition site will help to expand our
understanding of the mode of action of metalloporphyrins in RT
inhibition and will assist in the design and development of more potent
metalloporphyrin RT inhibitors for the management of HIV infection.
Copyright © 1999 by The American Society for Biochemistry and Molecular Biology, Inc.