Indexed by:期刊论文

Date of Publication:2013-10-01

Journal:CHEMICAL BIOLOGY & DRUG DESIGN

Included Journals:SCIE、PubMed、Scopus

Volume:82

Issue:4

Page Number:394-400

ISSN No.:1747-0277

Key Words:enthalpy; entropy; Gibbs free energy; hydrogen bond; isothermal titration calorimetry; thermodynamics

Abstract:The use of small molecule B-cell lymphoma 2 homology domain 3 mimetics to neutralize the B-cell lymphoma 2 protein is an attractive strategy for cancer treatment due to its ability to cause targeted cell apoptosis. We have previously reported the design and optimization of a series of B-cell lymphoma 2 homology domain 3-mimetics, called compounds 1-6. In this study, we evaluated the optimization of B-cell lymphoma 2 homology domain 3-mimetics from a thermodynamic perspective. Understanding the thermodynamic parameters of B-cell lymphoma 2 homology domain 3-mimetics plays a critical role in the development of B-cell lymphoma 2 small-molecule inhibitors. The thermodynamic parameters for the interactions of these compounds with the myeloid cell leukemia sequence 1 protein were obtained using isothermal titration calorimetry. Owing to compounds 1-6 overcoming enthalpy-entropy compensation, the affinities of them improved gradually. Toward binding to the myeloid cell leukemia sequence 1 protein, compound 6 was deemed optimal with an obtained K-d value of 238nm, which is a 10(4)-fold improvement compared with 1. Analysis of the enthalpy and -TS efficiencies showed that ligand efficiencies with respect to molecular size are correlated with the enthalpic efficiencies. Notably, an enthalpy gain of 4.65kcal/mol identified that an additional hydrogen bond is formed by 2 with myeloid cell leukemia sequence 1 compared with compound 1. For the first time, hydrogen bonding between a small-molecule inhibitor of B-cell lymphoma 2 was demonstrated experimentally.