Thymoquinone Blocks pSer/pThr Recognition by Plk1 Polo-Box Domain As a Phosphate MimicYin, Z., Song, Y., Rehse, P.H.
(2013) ACS Chem Biol 8: 303-308
- PubMed: 23135290
- DOI: https://doi.org/10.1021/cb3004379
- Primary Citation of Related Structures:
4H5X, 4H71, 4HCO
- PubMed Abstract:
Phosphorylation-dependent protein-protein interaction has rarely been targeted in medicinal chemistry. Thymoquinone, a naturally occurring antitumor agent, disrupts prephosphorylated substrate recognition by the polo-box domain of polo-like kinase 1, a key mitotic regulator responsible for various carcinogenesis when overexpressed. Here, crystallographic studies reveal that the phosphoserine/phosphothreonine recognition site of the polo-box domain is the binding pocket for thymoquinone and its analogue poloxime. Both small molecules displace phosphopeptides bound with the polo-box domain in a slow but noncovalent binding mode. A conserved water bridge and a cation-π interaction were found as their competition strategy against the phosphate group. This mechanism sheds light on small-molecule intervention of phospho-recognition by the polo-box domain of polo-like kinase 1 and other phospho-binding proteins in general.
School of Life Science and Technology, China Pharmaceutical University, 24 Tong Jia Xiang, Nanjing, Jiangsu 210009, China.