Heat capacity changes associated with G-quadruplex unfolding

Author:

Garabet Arees1,Liu Lutan1ORCID,Chalikian Tigran V.1ORCID

Affiliation:

1. Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto , 144 College Street, Toronto, Ontario M5S 3M2, Canada

Abstract

G-quadruplexes are four-stranded DNA structures that have been found in the cell and are thought to act as elements of control in genomic events. The measurements of the thermodynamic stability, ΔG, of G-quadruplexes shed light on the molecular forces involved in the stabilization of these structures. In thermodynamic studies, the differential heat capacity, ΔCP, of the folded and unfolded states of a G-quadruplex is a fundamental property that describes the temperature dependences of the differential enthalpy, ΔH, entropy, ΔS, and free energy, ΔG. Despite its recognized importance, the ΔCP of G-quadruplex unfolding has not been measured directly. Here, we use differential scanning calorimetry to evaluate changes in heat capacity, ΔCP, accompanying the unfolding transitions of G-quadruplexes formed by modified DNA sequences from the promoter regions of the c-MYC, VEGF, and Bcl-2 oncogenes. The average value of ΔCP is 0.49 ± 0.12 kcal mol−1 K−1. Our analysis revealed that disregarding ΔCP leads to significant errors in extrapolated values of the differential enthalpy, ΔH, and entropy, ΔS, of the folded and unfolded DNA conformations. Although the compensation between ΔH and ΔS weakens the effect of ΔCP on the differential free energy, ΔG, neglecting ΔCP may still result in relative errors in ΔG extrapolated to room temperature as great as 140%. We emphasize the importance of proper consideration of the effect of ΔCP in conformational studies of guanine-rich DNA molecules.

Funder

Natural Sciences and Engineering Research Council of Canada

Publisher

AIP Publishing

Subject

Physical and Theoretical Chemistry,General Physics and Astronomy

Cited by 2 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3