NMR Studies Reveal the Role of Biomembranes in Modulating Ligand Binding and Release by Intracellular Bile Acid Binding Proteins

Pedò, Massimo; Löhr, Frank; D’Onofrio, Mariapina; Assfalg, Michael; Dötsch, Volker; Molinari, Henríette

doi:10.1016/j.jmb.2009.10.014

Cited by 20 publications

(21 citation statements)

References 34 publications

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“…197,198 A recent NMR analysis of the ternary system composed of the bile acid binding protein, bile acids, and a membrane mimetic system revealed that the liver bile acid binding protein undergoes association with the anionic membrane, which induces its partial unfolding and the release of bile salts. 199 These studies are in agreement with earlier model studies, which described the release of retinol from the retinol-binding protein. 200,201 …”

Section: Active Factors Promoting Transient Disorder: Interaction-supporting

confidence: 91%

Conditionally and Transiently Disordered Proteins: Awakening Cryptic Disorder To Regulate Protein Function

2014

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Section: Active Factors Promoting Transient Disorder: Interaction-supporting

confidence: 91%

Conditionally and Transiently Disordered Proteins: Awakening Cryptic Disorder To Regulate Protein Function

2014

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“…The distribution of positively charged residues on the protein structure is shown in Figure . Previous dynamics simulation studies and indirect NMR evidence suggested that positively charged residues located in the antiportal region of the protein could establish electrostatic interaction with lipid head groups. This hypothesis has been now experimentally verified performing protein–lipid NMR titration experiments on three protein samples where a single lysine residue was mutated into alanine.…”

Section: Resultsmentioning

confidence: 99%

“…, step 1b), bile salt was added to each sample (Fig. , step 2b), causing the immediate release of the bound protein and the formation of holo proteins . The HSQC signal intensities were then immediately measured and the results are reported in Figure (b).…”

Section: Resultsmentioning

confidence: 99%

“…The membrane electrostatic surface potential was proposed to be a key physical parameter affecting protein structure . An NMR study demonstrated that bile salt binding shifts the equilibrium from a membrane‐bound, partially unstructured protein, to a free‐in‐solution ligand‐bound native state . Despite these investigations the molecular determinants of L‐BABP binding to membranes as well as the thermodynamics and kinetics of association equilibria are still not fully characterized.…”

Section: Introductionmentioning

confidence: 99%

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NMR investigation of the equilibrium partitioning of a water-soluble bile salt protein carrier to phospholipid vesicles

et al. 2013

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Membrane binding by cytosolic fatty acid binding proteins (FABP) appears to constitute a key step of intracellular lipid trafficking. We applied NMR spectroscopy to study the partitioning of a water-soluble bile acid binding protein (BABP), belonging to the FABP family, between its free and lipid-vesicle-bound states. As the lipid-bound protein was NMR-invisible, the signals of the free biomolecule were analyzed to obtain quantitative information on binding affinity and steady-state kinetics. The data indicated a reversible interaction of BABP with anionic vesicles occurring in a very slow exchange regime on the NMR time scale. The approximate binding epitope was demonstrated from results on BABP samples in which different positively charged lysine residues were mutated to neutral alanines. H/D exchange measurements indicated a higher exposure to solvent for the core amino acid residues in the liposome-bound state. Finally, the BABP-liposome interaction was also investigated for the first time through an MRI-chemical exchange saturation transfer experiment that has potential applications not only in the field of biology, but also in biomedicine, bioanalytical chemistry, and nanotechnology.

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“…They increase water solubility of hydrophobic molecules, they sequester free lipid molecules from the cytosol that protects the cell from their toxic effects, and they direct lipid cargo to the target compartments . ILBPs are expressed at high levels in several tissues, and their small size makes them efficient lipid chaperones . Therefore, it seems unlikely that ferritin simply acts as an alternate lipid carrier, although its observed K d is in the micromolar range.…”

Section: Discussionmentioning

confidence: 99%

Unsaturated Long‐Chain Fatty Acids Are Preferred Ferritin Ligands That Enhance Iron Biomineralization

Zanzoni

Pagano

D’Onofrio

et al. 2017

Chemistry A European J

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Ferritin is a ubiquitous nanocage protein, which can accommodate up to thousands of iron atoms inside its cavity. Aside from its iron storage function, a new role as a fatty acid binder has been proposed for this protein. The interaction of apo horse spleen ferritin (HoSF) with a variety of lipids has been here investigated through NMR spectroscopic ligand-based experiments, to provide new insights into the mechanism of ferritin-lipid interactions, and the link with iron mineralization. 1D H, diffusion (DOSY) and saturation-transfer difference (STD) NMR experiments provided evidence for a stronger interaction of ferritin with unsaturated fatty acids compared to saturated fatty acids, detergents, and bile acids. Mineralization assays showed that oleate c aused the most efficient increase in the initial rate of iron oxidation, and the highest formation of ferric species in HoSF. The comprehension of the factors inducing a faster biomineralization is an issue of the utmost importance, given the association of ferritin levels with metabolic syndromes, such as insulin resistance and diabetes, characterized by fatty acid concentration dysregulation. The human ferritin H-chain homopolymer (HuHF), featuring ferroxidase activity, was also tested for its fatty acid binding capabilities. Assays show that oleate can bind with high affinity to HuHF, without altering the reaction rates at the ferroxidase site.

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NMR Studies Reveal the Role of Biomembranes in Modulating Ligand Binding and Release by Intracellular Bile Acid Binding Proteins

Cited by 20 publications

References 34 publications

Conditionally and Transiently Disordered Proteins: Awakening Cryptic Disorder To Regulate Protein Function

Conditionally and Transiently Disordered Proteins: Awakening Cryptic Disorder To Regulate Protein Function

NMR investigation of the equilibrium partitioning of a water-soluble bile salt protein carrier to phospholipid vesicles

Unsaturated Long‐Chain Fatty Acids Are Preferred Ferritin Ligands That Enhance Iron Biomineralization

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