Sanyal Dwipanjan, Muzata Danny, Uversky Vladimir N, Kharbanda Surender, Chowdhury Sourav, Jasuja Ravi
XYone Therapeutics, Canton, MA, USA.
Department of Computer Science and Information Systems, Birla Institute of Technology and Science-Pilani, Hyderabad, India.
Biochem Biophys Res Commun. 2025 Aug 15;775:152114. doi: 10.1016/j.bbrc.2025.152114. Epub 2025 May 29.
Antibody-drug conjugates (ADCs) represent a transformative approach in cancer therapy, combining the specificity of monoclonal antibodies with targeted delivery of potent cytotoxic drugs to tumors. Discovery of novel antigens has been the hallmark for development of ADC therapeutics and MUC1 is one such oncoprotein, which has garnered renewed interest recently. The 3D1 antibody, engineered to bind specifically to the alpha 3 (α3) helix of the MUC1-C/extracellular domain, is being actively developed towards clinical translation. The study examined the conformational coupling in the residues spanning the MUC1 sea urchin sperm protein, enterokinase, and agrin domain (SEA), which incorporates MUC1-C. 3D1 has been shown to be sensitive to three specific point mutations-D85E, V86A, and T88A- at the interaction surface between MUC1-C and the 3D1 antibody. Our findings reveal that D85E and T88A mutations cause significant conformational shifts and reduced binding affinity due to altered electrostatic interactions and hydrogen bonding. The V86A mutation, while maintaining the overall conformation, disrupts local hydrophobic interactions, leading to decreased binding efficiency. Further, residue 85 in the wild-type (WT) MUC1 SEA domain interacts with other residues, contributing to local frustration and destabilization. Mutants D85E, V86A, and T88A exhibited similar frustration patterns but with increased local energy, indicating reduced stability. Frustration calculations highlighted the crucial role of the α3 helix in protein stability and antibody interaction. Collectively, these data highlight the importance of specific residues contributing to the local frustration in maintaining effective antibody binding and suggest that mutations impacting these residues can significantly alter antigen binding dynamics.
抗体药物偶联物（ADCs）是癌症治疗中的一种变革性方法，它将单克隆抗体的特异性与向肿瘤靶向递送强效细胞毒性药物相结合。发现新型抗原一直是ADC疗法发展的标志，而MUC1就是这样一种癌蛋白，最近它重新引起了人们的关注。经过工程改造以特异性结合MUC1-C/细胞外结构域α3（α3）螺旋的3D1抗体正在积极推进临床转化。该研究考察了包含MUC1-C的MUC1海胆精子蛋白、肠激酶和集聚蛋白结构域（SEA）中各残基的构象偶联。3D1已被证明对MUC1-C与3D1抗体相互作用表面的三个特定点突变——D85E、V86A和T88A敏感。我们的研究结果表明，D85E和T88A突变由于静电相互作用和氢键的改变导致显著的构象变化和结合亲和力降低。V86A突变虽然保持了整体构象，但破坏了局部疏水相互作用，导致结合效率降低。此外，野生型（WT）MUC1 SEA结构域中的85位残基与其他残基相互作用，导致局部无序和不稳定。突变体D85E、V86A和T88A表现出相似的无序模式，但局部能量增加，表明稳定性降低。无序计算突出了α3螺旋在蛋白质稳定性和抗体相互作用中的关键作用。总体而言，这些数据突出了特定残基在维持有效抗体结合中对局部无序的重要性，并表明影响这些残基的突变可显著改变抗原结合动力学。
