Fig. 4: Conserved Cys232 of PorG forms a disulphide bond with a conserved Cys356 of PorK.
From: Insights into type IX secretion from PorKN cogwheel structure bound to PorG and attachment complexes
A AlphaFold3 model of PorG (green)-PorK(pink) interaction showing the close proximity of the PorG Cys232 and PorK Cys356 (circled). Cys residues are shown in ball rendering B SDS-PAGE of purified PorKNG complex electrophoresed under reducing (DTT+) and non-reducing (DTT−) conditions. C MS/MS spectra consistent with a disulphide bond peptide between PorG (230TFCNKQ235) and PorK (355GCFLGNFKPGEGDYTADGHLIPSR378). D SDS-PAGE of purified PorKNG complex under reducing conditions. E Cryo-EM images of the PorKN rings showing the purified dual ring structure (NK-KN) in the presence (top panel) and absence of DTT (bottom panel). Scale bars: 50 nm. Source data are provided as a Source Data file.
