Fig. 6: The #4-helix within the C-segment of LBP interacts with oxidized TGs. | Nature Communications

Fig. 6: The #4-helix within the C-segment of LBP interacts with oxidized TGs.

From: Lipopolysaccharide binding protein resists hepatic oxidative stress by regulating lipid droplet homeostasis

Fig. 6

a LBP structure solved in the PDB database and predicted by Alphafold, with the black box indicating the differential #4α-helix. b Predict secondary structures and perform homology comparisons of LBP in various mammals. c Molecular docking diagram of WT-Tridocosahexaenoin with LBP. LBP is represented as a dark blue cartoon model, while the ligand is depicted as a cyan stick model. The binding site is shown as a magenta stick structure. (yellow: Hydrogen bonds, magenta: ionic interactions, and green dashed lines: hydrophobic interactions). d Molecular docking diagram of oxidized-Tridocosahexaenoin with LBP. e Representative co-stained images captured by confocal microscope showing the expression of C-segment LBP-GFP (LBPSP+216-481-GFP, green) for 48 h, treated with Bodipy C12 (orange) or Bodipy C12+PC for 16 h. Experiments repeated three times independently with similar results. f Representative co-stained images captured by confocal microscope showing the expression of H294A mutation (green) and H294G mutation (green) for 48 h, treated with Bodipy C12 (orange) for 16 h. Experiments repeated five times independently with similar results. g Comparison of Alphafold predicted LBPWT(green) and LBPF436L(blue) protein structures. The F436L site is indicated in red (upper panel). h Representative confocal images of expression LBPF436L-GFP (green) for 48 h and co-stained after adding Bodipy C12 (orange) for 16 h. Experiments repeated five times independently with similar results. i Hepatic TG content of LBP−/− mice with overexpressing LBPWT-GFP or LBPF436L-GFP. Shown are means ± s.d., two-tailed unpaired t-test (n = 3, biologically independent). j Working model for LBP and PRDX4 interactions: 1. LBP expression upregulated response to oxidative stress; 2. LBP translocation to LD for promoting LD growth; 3. PRDX4 resolution promoting the export of LBP from the LDs; 4. Export of LBP enhancing lipolysis and phospholipid synthesis. Illustration by Mo Liu, with permission.

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