Fig. 2: PAPP-A dimerization mechanism.
From: Structure of the PAPP-ABP5 complex reveals mechanism of substrate recognition
a Overall cryo-EM structure of PAPP-ABP5 in surface representation showed that PAPP-A exists as a dimer in trans. PAPP-A chain A and chain B are colored in wheat and blue, respectively. IGFBP5 anchor peptide is shown as a cartoon in dark orange. b (Left) Surface representation of the CCP2 and LG domain interaction. The CCP2 and LG domains are colored in wheat and purple, respectively. (Right) Close-up view of the interface between the CCP2 and LG domains. The crucial hydrophobic residues in the interface are highlighted as sticks. c (Top) Close-up view of the overall PAPP-A dimer interface with the two key loop regions highlighted in box. (Bottom) The enlarged interface with the two loop regions highlighted by different colors: residues 1068-1078 (loop 1) in green, and residues 1100-1111 (loop 2) in gray. d Size-exclusion chromatography (SEC) of recombinant purified WT PAPP-A, and the three monomer variants at 1.4 μM concentration. WT PAPP-A behaves as a stable dimer, whereas all three variants show shifts to monomer fractions. WT PAPP-A and monomeric variants were purified as auto-cleaved products. UV absorbance chromatograms (top) as well as Coomassie-stained fractions of reduced SDS-PAGE gel (bottom) are shown. Data points are representative of n = 3 independent replicates. Source data are provided as a source data file.
