Erkanli Mehmet Emre, Kang Ted Keunsil, Kirsch Thorsten, Turley Eva A, Kim Jin Ryoun, Cowman Mary K
Department of Chemical and Biomolecular Engineering, Tandon School of Engineering New York University Brooklyn New York USA.
Department of Biomedical Engineering, Tandon School of Engineering New York University New York New York USA.
Proteoglycan Res. 2024 Jul-Sep;2(3):e70001. doi: 10.1002/pgr2.70001. Epub 2024 Sep 10.
Peptides that increase pro-reparative responses to injury and disease by modulating the functional organization of hyaluronan (HA) with its cell surface binding proteins (e.g., soluble receptor for hyaluronan-mediated motility [RHAMM] and integral membrane CD44) have potential therapeutic value. The binding of RHAMM to HA is an attractive target, since RHAMM is normally absent or expressed at low levels in homeostatic conditions, but its expression is significantly elevated in the extracellular matrix during tissue stress, response-to-injury, and in cancers and inflammation-based diseases. The HA-binding site in RHAMM contains two closely spaced sequences of clustered basic amino acids, in an alpha-helical conformation. In the present communication, we test whether an alpha-helical conformation is required for effective peptide binding to HA, and competitive disruption of HA-RHAMM interaction. The HA-binding RHAMM-competitive peptide P15-1, identified using the unbiased approach of phage display, was examined using circular dichroism spectroscopy and the conformation-predictive AI-based AlphaFold2 algorithm. Unlike the HA-binding site in RHAMM, peptide P15-1 was found to adopt irregular conformations in solution rather than alpha helices. Instead, our structural analysis suggests that the primary determinant of peptide-HA binding is associated with a specific clustering and spacing pattern of basic amino acids, allowing favorable electrostatic interaction with carboxylate groups on HA.
通过调节透明质酸（HA）与其细胞表面结合蛋白（例如，透明质酸介导的运动可溶性受体[RHAMM]和整合膜CD44）的功能组织来增强对损伤和疾病的促修复反应的肽具有潜在的治疗价值。RHAMM与HA的结合是一个有吸引力的靶点，因为在稳态条件下RHAMM通常不存在或低水平表达，但在组织应激、损伤反应以及癌症和炎症性疾病期间，其在细胞外基质中的表达会显著升高。RHAMM中的HA结合位点包含两个紧密间隔的成簇碱性氨基酸序列，呈α螺旋构象。在本通讯中，我们测试了有效的肽与HA结合以及竞争性破坏HA-RHAMM相互作用是否需要α螺旋构象。使用噬菌体展示的无偏方法鉴定的HA结合RHAMM竞争性肽P15-1，通过圆二色光谱和基于构象预测的人工智能AlphaFold2算法进行了检测。与RHAMM中的HA结合位点不同，发现肽P15-1在溶液中采用不规则构象而非α螺旋。相反，我们的结构分析表明，肽与HA结合的主要决定因素与碱性氨基酸的特定聚类和间隔模式有关，从而允许与HA上的羧基进行有利的静电相互作用。
