{"database":"biostudies-literature","file_versions":[],"scores":null,"additional":{"omics_type":["Unknown"],"volume":["15(5)"],"submitter":["Nie J"],"pubmed_abstract":["Cation-π interaction is an electrostatic interaction between a cation and an electron-rich arene. It plays an essential role in many biological systems as a vital driving force for protein folding, stability, and receptor-ligand interaction/recognition. To date, the discovery of most cation-π interactions in proteins relies on the statistical analyses of available three-dimensional (3D) protein structures and corresponding computational calculations. However, their experimental verification and quantification remain sparse at the molecular level, mainly due to the limited methods to dynamically measure such a weak non-covalent interaction in proteins. Here, we use atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) to measure the stability of protein neutrophil gelatinase-associated lipocalin (also known as NGAL, siderocalin, lipocalin 2) that can bind iron through the cation-π interactions between its three cationic residues and the iron-binding tri-catechols. Based on a site-specific cysteine engineering and anchoring method, we first characterized the stability and unfolding pathways of apo-NGAL. Then, the same NGAL but bound with the iron-catechol complexes through the cation-π interactions as a holo-form was characterized. AFM measurements demonstrated stronger stabilities and kinetics of the holo-NGAL from two pulling sites, F122 and F133. Here, NGAL is stretched from the designed cysteine close to the cationic residues for a maximum unfolding effect. Thus, our work demonstrates high-precision detection of the weak cation-π interaction in NGAL.<h4>Electronic supplementary material</h4>Supplementary material (additional SDS-PAGE, UV-vis, protein sequences, and more experimental methods) is available in the online version of this article at 10.1007/s12274-021-4065-9."],"journal":["Nano research"],"pagination":["4251-4257"],"full_dataset_link":["https://www.ebi.ac.uk/biostudies/studies/S-EPMC9077643"],"repository":["biostudies-literature"],"pubmed_title":["Detection of weak non-covalent cation-π interactions in NGAL by single-molecule force spectroscopy."],"pmcid":["PMC9077643"],"pubmed_authors":["Tian F","Shi S","Nie J","Zheng P","Deng Y"],"additional_accession":[]},"is_claimable":false,"name":"Detection of weak non-covalent cation-π interactions in NGAL by single-molecule force spectroscopy.","description":"Cation-π interaction is an electrostatic interaction between a cation and an electron-rich arene. It plays an essential role in many biological systems as a vital driving force for protein folding, stability, and receptor-ligand interaction/recognition. To date, the discovery of most cation-π interactions in proteins relies on the statistical analyses of available three-dimensional (3D) protein structures and corresponding computational calculations. However, their experimental verification and quantification remain sparse at the molecular level, mainly due to the limited methods to dynamically measure such a weak non-covalent interaction in proteins. Here, we use atomic force microscopy-based single-molecule force spectroscopy (AFM-SMFS) to measure the stability of protein neutrophil gelatinase-associated lipocalin (also known as NGAL, siderocalin, lipocalin 2) that can bind iron through the cation-π interactions between its three cationic residues and the iron-binding tri-catechols. Based on a site-specific cysteine engineering and anchoring method, we first characterized the stability and unfolding pathways of apo-NGAL. Then, the same NGAL but bound with the iron-catechol complexes through the cation-π interactions as a holo-form was characterized. AFM measurements demonstrated stronger stabilities and kinetics of the holo-NGAL from two pulling sites, F122 and F133. Here, NGAL is stretched from the designed cysteine close to the cationic residues for a maximum unfolding effect. Thus, our work demonstrates high-precision detection of the weak cation-π interaction in NGAL.<h4>Electronic supplementary material</h4>Supplementary material (additional SDS-PAGE, UV-vis, protein sequences, and more experimental methods) is available in the online version of this article at 10.1007/s12274-021-4065-9.","dates":{"release":"2022-01-01T00:00:00Z","publication":"2022","modification":"2026-03-18T13:18:29.151Z","creation":"2025-04-19T07:25:06.009Z"},"accession":"S-EPMC9077643","cross_references":{"pubmed":["35574260"],"doi":["10.1007/s12274-021-4065-9"]}}