Fig. 2: Electrostatic interactions drive MVP-PARP4 complex formation.
From: Structural insights into the roles of PARP4 and NAD+ binding in the human vault cage
a Atomic model (left) of the binding interface between the PARP4 MINT (blue) and MVP3-5 repeat domains (gray) from the FL PARP4-MVP structure (inset). MINT domain helices located at the PARP4-MVP interface are labeled with the letter h and associated helix number. Key residues from PARP4 and MVP are labeled in blue and gray, respectively. b The exposed interfaces of MINT (blue) and MVP (gray) are shown in cartoon (left) and surface (right) view representations. Critical interaction residues are labeled in black, with labels of additional residues that may support the interaction shown in gray. Surface views of the MINT and MVP3-5 models are colored by relative electrostatic potential (right), demonstrating electrostatic and steric complementarity at the interface. c Size exclusion chromatograms show individual traces of MVP3-5 (gray) and MINT constructs (blue), indicating their absorbance at 280 nm (upper). Individual traces are overlaid with complex traces following co-incubation of the WT (pink, left) and double mutant constructs (red, right). Corresponding SDS-PAGE gels (lower) from SEC binding assays showing co-elution of WT MVP3-5 and MINT (left) and the separate elutions of double mutant constructs (right) following their respective co-incubations and injections over a Superdex 75 increase column. Black bars denote the area over which fraction samples were collected, and numbers in the input lanes are shown in colors that correspond to the protein labels in the SEC traces above. The experiment was performed twice.
