Fig. 1: The atomic structure of BAI3 N-terminal domains bound to the C1q-like domain trimers of C1ql3 reveals that BAI3 N-terminal domains represent an atypical CUB domain that nestles into the asymmetric interfaces between two C1q-like domains.
From: Structure of the complex of C1q-like 3 protein with adhesion-GPCR BAI3
a The isolated BAI3 NTD (residues 26–290) forms a tight stoichiometric complex with the C1q-like domain trimer of C1ql3 (residues 122-255), as monitored by size-exclusion chromatography (left) and Coomassie-stained SDS-PAGE gels (right). b Overall structure of C1q-like domain trimer from C1ql3 (colored in different shades of orange) in a complex with BAI3 NTDs (cyan). Ca2+-ions are shown as gray spheres, and selected N- and C-termini are identified. c Molecular determinants of BAI3 NTD (cyan) and C1ql3 C1q-like domain (orange) interactions. Ca2+-ions are shown as gray spheres and interacting residues as sticks, while hydrogen bonds or salt bridges are indicated by dashed gray lines. d Structure superposition of the BAI3 NTD (cyan) with the C1R CUB domain (magenta; top hit ranked by DALI search). e Structure superposition of mouse Alpha Fold predicted BAI1 NTD (light magenta) to BAI3 NTD (cyan). f Detailed C1ql3-BAI NTD interaction with Alpha Fold predicted BAI1 NTD (light magenta) superposed to BAI3 NTD (cyan). T65 mutation from BAI3 to R78 in BAI1 leads to steric clashes with interacting C1ql3.
