Fig. 2: Molecular architecture of KOGG quaternary complex.

a Overview of the intermolecular contacts within the KOGG complex. The protomers are depicted as a cartoon model, with secondary structures involved in complex formation highlighted in pink/red for LH3 and in blue/cyan for ColGalT1. Interfaces mediating complex assembly indicated by dotted frames. The N-linked glycosylations were depicted as surface models in magenta. b Enlarged views of the LH3 dimeric interface. LH3 is shown as a cartoon model, and the contacting residues are displayed as a stick model, colored according to the elements. c Enlarged views of the ColGalT1 dimeric interface. ColGalT1 is shown as a cartoon model, and the contacting residues are displayed as a stick model, colored according to the elements. The N-linked glycan moieties were shown as stick models, colored according to the elements (C-N-O: magenta-blue-red). d Enlarged view of the LH3-ColGalT1 interface. The N-loop of ColGalT1^U is shown as a cartoon model colored in light blue, while the GalT-N of ColGalT1^V is shown as a calculated solvent-accessible electrostatic surface potential map. The contacting residues from the N-loop^U, GalT-N^V, and GlcT^B are displayed as a stick model, colored according to the elements (light blue-red-blue for N-loop^U and GalT-N^V; pink-red-blue for LH3^B). e The interactions between N-loop of ColGalT1 and LH3. The protomer B of LH3 is shown as a calculated solvent-accessible electrostatic surface potential map and sliced to show the slit between its AC and GlcT domain. The N-loop of ColGalT1^U was shown as stick model colored by elements. f, g The interactions between LH3 and ColGalT1. The 293 T cells were co-transfected with LH3/PLOD3 wild-type or variants with flag-tag and GLT25D1/ColGalT1 wild-type or variants with Strep-tag. Shown were the representative immunoblot results from three independent experiments of the pulldown of LH3 and ColGalT1 by the Strep-tagged ColGalT1 using strep-tactin affinity resin (f) and the Flag-tagged LH3 using anti-Flag affinity resin (g), as well as the immunoblot results of lysates.