Conformational Adaptation of Annexin V upon Binding to Liposomes: A Time-Resolved Fluorescence Study

Follenius-Wund, Anny; Piémont, Étienne; Freyssinet, Jean‐Marie; Gérard, Dominique; Pigault, Claire

doi:10.1006/bbrc.1997.6596

Cited by 17 publications

(23 citation statements)

References 33 publications

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“…On the other hand, a single Trp residue in the calcium binding protein annexin was reported to exhibit two distinct lifetimes of 2.0 ns and 7.0 ns when annexin is associated to lipid vesicles. 34 The 7.0 ns decay was attributed to the Trp side-chain located in a more polar environment, at the interface between the protein surface and the lipid membrane. 34 Thus, to further explore the dynamic behavior of the Trp side chain, a 250 ns molecular dynamics simulation was analyzed and the solvent accessible surface area (SASA) plot for Trp169 is shown in Figure 7.…”

Section: Discussionmentioning

confidence: 99%

“…34 The 7.0 ns decay was attributed to the Trp side-chain located in a more polar environment, at the interface between the protein surface and the lipid membrane. 34 Thus, to further explore the dynamic behavior of the Trp side chain, a 250 ns molecular dynamics simulation was analyzed and the solvent accessible surface area (SASA) plot for Trp169 is shown in Figure 7. The Trp side chain samples three major conformations with distinct SASA values.…”

Section: Discussionmentioning

confidence: 99%

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Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

et al. 2015

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Downstream Regulatory Element Antagonist Modulator (DREAM) belongs to the family of neuronal calcium sensors (NCS) that transduce the intracellular changes in Ca 21 concentration into a variety of responses including gene expression, regulation of Kv channel activity, and calcium homeostasis. Despite the significant sequence and structural similarities with other NCS members, DREAM shows several features unique among NCS such as formation of a tetramer in the apo-state, and interactions with various intracellular biomacromolecules including DNA, presenilin, Kv channels, and calmodulin. Here we use spectroscopic techniques in combination with molecular dynamics simulation to study conformational changes induced by Ca 21 /Mg 21 association to DREAM. Our data indicate a minor impact of Ca 21 association on the overall structure of the Nand C-terminal domains, although Ca 21 binding decreases the conformational heterogeneity as evident from the decrease in the fluorescence lifetime distribution in the Ca 21 bound forms of the protein. Time-resolved fluorescence data indicate that Ca 21 binding triggers a conformational transition that is characterized by more efficient quenching of Trp residue. The unfolding of DREAM occurs through an partially unfolded intermediate that is stabilized by Ca 21 association to EF-hand 3 and EF-hand 4. The native state is stabilized with respect to the partially unfolded state only in the presence of both Ca 21 and Mg 21 suggesting that, under physiological conditions, Ca 21 free DREAM exhibits a high conformational flexibility that may facilitate its physiological functions.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

et al. 2015

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“…The crystal structure of annexin V complexed with phospholipid headgroup analogues reveals close contacts between the glycerol backbone and the Trp185 side chain (15), in good agreement with the fluorescence results. Recent time-resolved fluorescence studies show that the interfacially located tryptophan side chain may be in equilibrium with another conformation that penetrates into the lipid bilayer (25). Another possible function of the Trp185 side chain may be to position the annexin molecule along the membrane surface to maximize favorable interfacial contacts.…”

Section: Discussionmentioning

confidence: 99%

Mutational and Crystallographic Analyses of Interfacial Residues in Annexin V Suggest Direct Interactions with Phospholipid Membrane Components^,

Campos

Mealy

et al. 1998

Biochemistry

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Annexin V belongs to a family of eukaryotic calcium-dependent membrane-binding proteins. The calcium-binding sites at the annexin-membrane interface have been investigated in some detail; however, little is known about the functional roles of highly conserved interfacial residues that do not coordinate calcium themselves. In the present study, the importance of tryptophan 185, and threonine or serine at positions 72, 144, 228, and 303, in rat annexin V is investigated by site-directed mutagenesis, X-ray crystallography, and functional assays. The high-resolution crystal structures of the mutants show that the mutations do not cause structural perturbations of the annexin molecule itself or disappearance of bound calcium ions from calcium-binding sites. The assays indicate that relative to wild-type annexin V, loss of the methyl substituent at position 72 (Thr72-->Ser) has no effect while loss of the hydroxyl group (Thr72-->Ala or Thr72-->Lys) causes reduction of membrane binding. Multiple lysine substitutions (e.g., Thr72,Ser144,Ser228,Ser303-->Lys) have a greater adverse effect than the single lysine mutation, suggesting that in annexin V the introduction of potentially favorable electrostatic interactions between the lysine side chains and the net negatively charged membrane surface is not sufficient to overcome the loss of the hydroxyl side chains. Replacement of the unique tryptophan, Trp185, by alanine similarly decreases membrane binding affinity. Taken together, the data suggest that the side chains mutated in this study contribute to phospholipid binding and participate directly in intermolecular contacts with phospholipid membrane components.

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“…Protein folding before and after labeling was evaluated by exciting the protein solution at 283 nm and recording the emission spectra using a Luminescence Spectrometer (PerkinElmer, LS 55). An emission maximum at 320 nm confirmed that the protein was not denatured (27). …”

Section: Methodsmentioning

confidence: 97%

Peripheral Protein Organization and Its Influence on Lipid Diffusion in Biomimetic Membranes

et al. 2010

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Protein organization on biomembranes and their dynamics are essential for cellular function. It is not clear, however, how protein binding may influence the assembly of underlying lipids or how the membrane structure leads to functional protein organization. Toward this goal, we investigated the effects of annexin a5 binding to biomimetic membranes using fluorescence imaging and correlation spectroscopy. Annexin a5 (anx a5), a peripheral intracellular protein that plays a membrane remodeling role in addition to other functions, binds specifically and tightly to anionic (e.g., phosphatidylserine)-containing membranes in the presence of calcium ion. Our fluorescence microscopy reveals that annexin likely forms assemblies, along with a more dispersed population, upon binding to anionic biomembranes in the presence of calcium ion, which is reflected in its two-component Brownian motion. To investigate the effects of annexin binding on the underlying lipids, we used specific acyl chain-labeled phospholipid analogs, NBD-phosphatidylcholine (NBD-PC) and NBD-phosphatidylserine (NBD-PS). We find that both NBD-labeled lipids cluster under anx a5 assemblies, as compared with when they are found under the dispersed annexin population, and NBD-PS exhibits two-component lateral diffusion under the annexin assemblies. In contrast, NBD-PC diffusion is slower by an order of magnitude under the annexin assemblies in contrast to its diffusion when not localized under anx a5 assemblies. Our results indicate that upon binding to membranes, the peripheral protein annexin organizes the underlying lipids into domains, which may have functional implications in vivo.

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Conformational Adaptation of Annexin V upon Binding to Liposomes: A Time-Resolved Fluorescence Study

Cited by 17 publications

References 33 publications

Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Mutational and Crystallographic Analyses of Interfacial Residues in Annexin V Suggest Direct Interactions with Phospholipid Membrane Components^,

Peripheral Protein Organization and Its Influence on Lipid Diffusion in Biomimetic Membranes

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Conformational Adaptation of Annexin V upon Binding to Liposomes: A Time-Resolved Fluorescence Study

Cited by 17 publications

References 33 publications

Ca2+ and Mg2+ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Ca2+ and Mg2+ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Mutational and Crystallographic Analyses of Interfacial Residues in Annexin V Suggest Direct Interactions with Phospholipid Membrane Components,

Peripheral Protein Organization and Its Influence on Lipid Diffusion in Biomimetic Membranes

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Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Ca²⁺ and Mg²⁺ modulate conformational dynamics and stability of downstream regulatory element antagonist modulator

Mutational and Crystallographic Analyses of Interfacial Residues in Annexin V Suggest Direct Interactions with Phospholipid Membrane Components^,