DC-peptoid-1

DC-peptoid-1 is a specific binding agent and cross-linker for the phosphorylated Brd4 PDID region, exhibiting a dissociation constant (Kd) of approximately 50-100 μM for human targets. It selectively binds only phosphorylated PDID, without recognizing the non-phosphorylated form or other regions like Brd4 598-785. DC-peptoid-1 efficiently cross-links with target proteins in both solution and cell lysates and can successfully capture phosphorylated PDID from complex systems through immobilization. It does not bind to non-phosphorylated proteins from bacteria or other nonspecific phosphoproteins. This compound has the potential to serve as an alternative to phosphoprotein-specific antibodies in applications such as immunoaffinity purification.

Soluble DC-peptoid-1 binds with the phosphorylated PDID of the Brd4 protein, with an estimated Kd of 50-100 μM, and exhibits minimal affinity for unmodified PDID. Cys-DC-peptoid-1 can selectively capture the phosphorylated PDID domain of Brd4 from Sf9 cell lysates but does not bind unmodified PDID, while showing some non-specific binding to other components in the lysate. BD-DC-peptoid-1 (biotinylated DC-peptoid-1) (0.5 μM) can specifically cross-link with 0.5 μM phosphorylated Brd4 protein in solution in the presence of 2 mM NaIO4. Additionally, BD-DC-peptoid-1 (0.5 μM) cross-links with phosphorylated Brd4 protein in whole Sf9 cell lysates under the same conditions, albeit with some non-specific cross-linking to other proteins in the lysate.