Quantitative Chemical Proteomics Reveals Interspecies Variations on Binding Schemes of L-FABP with Perfluorooctanesulfonate

Abstract

Evaluating interspecies toxicity variation is a long-standing challenge for chemical hazard assessment. This study developed a quantitative interspecies thermal shift assay (QITSA) for in situ, quantitative, and modest-throughput investigation of chemical–protein interactions in cell and tissue samples across species. By using liver fatty acid binding protein (L-FABP) as a case study, the QITSA method was benchmarked with six per- and polyfluoroalkyl substances, and thermal shifts (ΔT m) were inversely related to their dissociation constants (R 2 = 0.98). The QITSA can also distinguish binding modes of chemicals exemplified by palmitic acid. The QITSA was applied to determine the interactions between perfluorooctanesulfonate (PFOS) and L-FABP in liver cells or tissues from humans, mice, rats, and zebrafish. The largest thermal stability enhancement by PFOS was observed for human L-FABP followed by the mouse, rat, and zebrafish. While endogenous ligands were revealed to partially contribute to the large interspecies variation, recombinant proteins were employed to confirm the high binding affinity of PFOS to human L-FABP, compared to the rat and mouse. This study implemented an experimental strategy to characterize chemical–protein interactions across species, and future application of QITSA to other chemical contaminants is of great interest.

Disclosing Environmental Ligands of L-FABP and PPARγ: Should We Re-evaluate the Chemical Safety of Hydrocarbon Surfactants?

“…Then, we performed molecular docking to better understand the structure-related interactions between hydrocarbon surfactants and L-FABP. Taking dodecyl benzenesulfonate as an example, three hydrogen bonds were formed between the negatively charged sulfonate group and residues of Arg-122, Ser-39, and Ser-124 (Figure S7), which was similar to results previously reported for PFAS. ,, In addition, the alkyl chain formed hydrophobic contacts with the interior cavity of L-FABP. It has been demonstrated that both the hydrogen bond and the hydrophobic interactions are crucial in stabilizing the ligand-protein complex of L-FABP. , Since these hydrocarbon surfactants have similar acidic head groups (SO 3 – and SO 4 – ), the stronger hydrophobic effects of longer-chain hydrocarbon surfactants may explain their stronger binding affinities to L-FABP …”

“…Taking dodecyl benzenesulfonate as an example, three hydrogen bonds were formed between the negatively charged sulfonate group and residues of Arg-122, Ser-39, and Ser-124 (Figure S7), which was similar to results previously reported for PFAS. 32,47,51 In addition, the alkyl chain formed hydrophobic contacts with the interior cavity of L-FABP. It has been demonstrated that both the hydrogen bond and the hydrophobic interactions are crucial in stabilizing the ligand-protein complex of L-FABP.…”

Insights into the Competitive Mechanisms of Per- and Polyfluoroalkyl Substances Partition in Liver and Blood

“…Up to now, there is sparse information on the interaction of the target PFASs with mouse L-FABP and serum albumin. Since mouse L-FABP (84.3%) 47 and serum albumin (72.4%) 48 have high identities with humans, we investigated the relationships between R L/S obtained from mice and log K d (hL-FABP) /log K d (HSA) , to further verify the competitive binding mechanisms in liver-blood partition. As expected, there were strong negative correlations between the R L/S and log K d (hL-FABP) /log K d (HSA) (Figure 3, Table S8, and Correlations 1 and 2).…”

Zebrafish facilitate non‐alcoholic fatty liver disease research: Tools, models and applications

“…[43][44][45] Furthermore, transcriptomic and proteomics analysis of zebrafish upon exposure to drugs or environmental factors can be easily performed to predict gene function related to specific phenotypes and to reveal gene networks and signalling pathways. 41,[46][47][48][49] Transcriptomics and proteomics analysis of the interleukin 6 (IL6)-overexpressed liver revealed a deregulation of glycolysis/gluconeogenesis pathway. 50 In addition, more research has linked metabolic processes to gene expression.…”