Cyclarity Therapeutics, 8001 Redwood Blvd Novato, CA 94945, USA; Departamento de Física Aplicada, Facultade de Física, Universidade de Santiago de Compostela, E-15782 Santiago de Compostela, Spain; Departamento de Química Orgánica, Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS), Universidade de Santiago de Compostela, Campus Vida s/n, E-15782 Santiago de Compostela, Spain.
Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), via P. Gobetti 101, Bologna 40129, Italy.
Carbohydr Polym. 2024 Jan 1;323:121360. doi: 10.1016/j.carbpol.2023.121360. Epub 2023 Sep 9.
A class of cyclodextrin (CD) dimers has emerged as a potential new treatment for atherosclerosis; they work by forming strong, soluble inclusion complexes with oxysterols, allowing the body to reduce and heal arterial plaques. However, characterizing the interactions between CD dimers and oxysterols presents formidable challenges due to low sterol solubility, the synthesis of modified CDs resulting in varying number and position of molecular substitutions, and the diversity of interaction mechanisms. To address these challenges and illuminate the nuances of CD-sterol interactions, we have used multiple orthogonal approaches for a comprehensive characterization. Results obtained from three independent techniques - metadynamics simulations, competitive isothermal titration calorimetry, and circular dichroism - to quantify CD-sterol binding are presented. The objective of this study is to obtain the binding constants and gain insights into the intricate nature of the system, while accounting for the advantages and limitations of each method. Notably, our findings demonstrate ∼1000× stronger affinity of the CD dimer for 7-ketocholesterol in comparison to cholesterol for the 1:1 complex in direct binding assays. These methodologies and findings not only enhance our understanding of CD dimer-sterol interactions, but could also be generally applicable to prediction and quantification of other challenging host-guest complex systems.
一类环糊精（CD）二聚体已成为治疗动脉粥样硬化的一种有潜力的新方法；它们通过与氧化固醇形成强而稳定的可溶性包合复合物，使身体能够减少和治愈动脉斑块。然而，由于固醇溶解度低、修饰后的 CD 的合成导致分子取代的数量和位置发生变化，以及相互作用机制的多样性，因此表征 CD 二聚体与氧化固醇之间的相互作用具有很大的挑战性。为了应对这些挑战并阐明 CD-固醇相互作用的细微差别，我们使用了多种正交方法进行全面表征。本文介绍了使用三种独立技术——元动力学模拟、竞争等温滴定量热法和圆二色性——来定量 CD-固醇结合的结果。本研究的目的是获得结合常数，并深入了解该体系的复杂性质，同时考虑每种方法的优缺点。值得注意的是，我们的发现表明，在直接结合实验中，与胆固醇相比，CD 二聚体对 7-酮胆固醇的亲和力要强约 1000 倍，形成 1:1 复合物。这些方法和发现不仅增强了我们对 CD 二聚体-固醇相互作用的理解，而且可能普遍适用于其他具有挑战性的主体-客体复杂体系的预测和定量。
