Abstract submission form for
School of Medicine Postgraduate Research Symposium
Thursday 6 June 2019, room na1.417 Waurn Ponds Campus
NAME
VIET CUONG PHAM
SUPERVISOR/S
WEI DUAN
Please consider my
abstract for:
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of the day you would like to
be considered for)
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TITLE
Thermodynamic and kinetic insights into CD81-DNA aptamer
interactions
AUTHORS
Cuong Viet Pham, Wang Yin, Yumei Zhang, Phuong Tran, Wei Duan
ABSTRACT
(250 words)
Aptamers are novel theranostic tools with promising clinical potential have drawn significant
attention both in the biomedical research and pharmaceutical industry. In addition to unique
advantages over traditional antibodies, aptamers may also be used as specific and robust ligands in
terms of interaction with their target proteins. Although knowledge of the protein-aptamer binding
is central to assess the aptamer performance, studies exploring the thermodynamic and kinetic
aspects of the interaction remain scarce. With the aim of employing aptamers as diagnostic tools,
we, at the first steps, investigated the thermodynamic and kinetic profiles of interactions between
CD81 large extracellular loop (LEL) and two different CD81 aptamers (namely, 2F-2 and 2J-6) to
explore molecular mechanisms underlying aptamer-CD81 interaction as well as to map the site of
binding . Our CD81 aptamers showed quite similar binding affinities to CD81 (K
D
of ~70 nM)
compared with that measured using flow cytometry. However, we have observed very different
thermodynamic properties with Isothermal Titration Calorimetry. Therein, 2F-2 aptamer
exothermically bound to soluble CD81 LEL via 1:1 binding model fitting and corresponding
association rate constant (k
on
), dissociation rate constant (k
off
) were 2.32 × 10
4
M
-1
s
-1
and 2.63 × 10
-
1
s
-1
respectively. Meanwhile, 2J-6 aptamer endothermically bound to the CD81 via a sequential
binding sites model. These differences in thermodynamics and binding models are likely associated
with discrepancies in the molecular mechanism of the binding and binding sites on CD81 as well.
Such findings pay the way to further engineering new CD81 aptamers with superior diagnostics
performance.