Simian virus 40 large T-antigen G-quadruplex DNA helicase inhibition by G-quadruplex DNA-interactive agents.
On the basis of growing evidence for G-quadruplex DNA structures in genomic DNA and the presumed need to resolve these structures for DNA replication, the G-quadruplex DNA unwinding ability of a prototypical replicative helicase, SV40 large T-antigen (T-ag), was investigated. Here, we demonstrate that this G-quadruplex helicase activity is robust and comparable to the duplex helicase activity of T-ag. Analysis of the SV40 genome demonstrates the presence of sequences that may form intramolecular G-quadruplexes, which are the presumed natural substrates for the G-quadruplex helicase activity of T-ag. A number of G-quadruplex-interactive agents as well as new perylene diimide (PDI) derivatives have been investigated as inhibitors of both the G-quadruplex and the duplex DNA helicase activities of T-ag. A unique subset of these G-quadruplex-interactive agents inhibits the G-quadruplex DNA unwinding activity of T-ag, relative to those reported to inhibit G-quadruplex DNA unwinding by RecQ-family helicases. We also find that certain PDIs are both potent and selective inhibitors of the G-quadruplex DNA helicase activity of T-ag. Surface plasmon resonance and fluorescence spectroscopic G-quadruplex DNA binding studies of these T-ag G-quadruplex helicase inhibitors have been carried out, demonstrating the importance of attributes in addition to binding affinity for G-quadruplex DNA that may be important for inhibition. The identification of potent and selective inhibitors of the G-quadruplex helicase activity of T-ag provides tools for probing the specific role of this activity in SV40 replication.
Tuesuwan
Bodin
B
Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, USA.
Kern
Jonathan T
JT
Thomas
Pei Wang
PW
Rodriguez
Mireya
M
Li
Jing
J
David
Wendi M
WM
Kerwin
Sean M
SM
D000952:Antigens, Polyomavirus Transforming / Q000276:immunology*; D001483:Base Sequence; D004247:DNA / Q000378:metabolism*; D004265:DNA Helicases / Q000037:antagonists & inhibitors*; D017931:DNA Primers; D013539:Simian virus 40 / Q000276:immunology*; D013050:Spectrometry, Fluorescence
D000952:Antigens, Polyomavirus Transforming; D017931:DNA Primers; D004247:DNA; D004265:DNA Helicases