title: Elucidation of the binding sites of sodium dodecyl sulfate to β-lactoglobulin using hydrogen/deuterium exchange mass spectrometry combined with docking simulation.
abstract: Hydrogen/deuterium exchange mass spectrometry (H/DX MS) has become a powerful tool to investigate protein-protein and protein-ligand interactions, but it is still challenging to localize the interaction regions/sites of ligands with pepsin-resistant proteins such as lipocalins. β-Lactoglobulin (BLG), a member of the lipocalin family, can bind a variety of small hydrophobic molecules including retinols, retinoic acids, and long linear fatty acids. However, whether the binding site of linear molecules locates in the external groove or internal cavity of BLG is controversial. In this study we used H/DX MS combined with docking simulation to localize the interaction sites of a tested ligand, sodium dodecyl sulfate (SDS), binding to BLG. H/DX MS results indicated that SDS can bind to both the external and the internal sites in BLG. However, neither of the sites is saturated with SDS, allowing a dynamic ligand exchange to occur between the sites at equilibrium state. Docking studies revealed that SDS forms H-bonds with Lys69 in the internal site and Lys138 and Lys141 in the external site in BLG via the sulfate group, and interacts with the hydrophobic residues valine, leucine, isoleucine and methionine within both of the sites via its hydrocarbon tail, stabilizing the BLG-SDS complex.
authors.affiliation: Beijing National Laboratory for Molecular Science, The CAS Key Laboratory of Analytical Chemistry for Living Biosystems, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Wenbing
authors.initials: W
authors.lastname: Hu
authors.forename: Jianan
authors.initials: J
authors.lastname: Liu
authors.forename: Qun
authors.initials: Q
authors.lastname: Luo
authors.forename: Yumiao
authors.initials: Y
authors.lastname: Han
authors.forename: Kui
authors.initials: K
authors.lastname: Wu
authors.forename: Shuang
authors.initials: S
authors.lastname: Lv
authors.forename: Shaoxiang
authors.initials: S
authors.lastname: Xiong
authors.forename: Fuyi
authors.initials: F
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D041961:Deuterium Exchange Measurement / Q000379:methods*; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D007782:Lactoglobulins / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry* / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D000596:Amino Acids; D007782:Lactoglobulins; D010446:Peptide Fragments; D012967:Sodium Dodecyl Sulfate