Binding of L-Argininamide to a DNA Aptamer: A Volumetric Study

作者：Liu Lutan; Stepanian Lora; Dubins David N; Chalikian Tigran V^*

来源：Journal of Physical Chemistry B, 2018, 122(31): 7647-7653.

DOI：10.1021/acs.jpcb.8b03912

We use a combination of volumetric and spectroscopic techniques to characterize the binding of L-argininamide to its aptamer, the 24-base DNA hairpin 5'-d(GATCGAAACGTAGCGCCTTCGATC)-3'. The binding causes increases in volume, Delta V, and adiabatic compressibility, Delta K-s, of 12 +/- 7 cm(3) mol(-1) bar and (73 +/- 8) x 10(-4) cm(3) mol(-1) bar(-1), respectively. These volumetric results combined with structural data reveal that the binding is accompanied by release of 73 +/- 27 waters from the hydration shells of the interacting molecules to the bulk. We use the estimated change in hydration to estimate the hydration, Delta S-hyd, and configurational, Delta S-conf, contributions to the binding entropy. The large and unfavorable change in configurational entropy, Delta S-conf, is nearly compensated by a favorable change in the hydration contribution, Delta S-hyd.

• 出版日期2018-8-9