Acid induced equilibrium unfolding of annexin V wild type shows two intermediate states

Beermann, Br. Bernd; Hinz, Hans‐Jürgen; Hofmann, Andreas; Huber, Robert

doi:10.1016/s0014-5793(98)00105-7

Cited by 27 publications

(23 citation statements)

References 13 publications

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“…The maximum of the fluorescence emission stays at 338-340 nm, similar to values found for Trp at the membrane/water interface in model peptides (60). Moreover, a similar value of the maximum of fluorescence emission of W187 has been reported recently in moderately acidic pH conditions in the absence of membranes (37,38). A similar effect is observed in the present work in reverse micelles in the absence of calcium.…”

Section: Discussionsupporting

confidence: 91%

“…Two main observations were made by the latter studies which exploit the presence of the single tryptophan residue (W187) in domain III: the fluorescence intensity increased by a factor of ∼4 and the emission maximum was red-shifted by around 12-15 nm upon binding of the protein to negatively charged phospholipid membranes in the presence of calcium. This change of the emission maximum is similar to the one induced by calcium in the absence of membranes (36) and by mild acidic conditions (37,38), leading to the exposure of the W187 residue on the protein surface where it is more mobile (34,36,38).…”

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confidence: 56%

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Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

et al. 1999

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The conformational dynamics of domain III in annexin V bound to negatively charged phospholipid vesicles of 1-palmitoyl-2-oleoyl-sn-glycerophosphocholine and 1-palmitoyl-2-oleoyl-sn-glycerophosphoserine or incorporated into reverse micelles of water/sodium bis(2-ethylhexyl) sulfosuccinate in isooctane, used to mimic the phospholipid/water interface, was studied by steady-state and time-resolved fluorescence of its single tryptophan residue (W187). Upon interaction with sonicated phospholipid vesicles in the presence of calcium, or upon incorporation into reverse micelles without calcium, a progressive 12-14 nm red shift of the fluorescence emission spectrum of W187 is observed. The indole environment becomes therefore more polar than in the unbound protein. Three major lifetime populations describe the fluorescence intensity decays of W187 in both systems. A long-lived excited-state population characterizes the membrane-bound state of the protein. The existence of local conformers with different subnanosecond mobility is suggested by specific association between lifetimes and correlation times both for the protein in buffer and in interaction with the membrane surface. The interaction of the protein with the membrane surface preserves the existence of a rapid unhindered rotational motion, which is coupled with all three lifetimes. The longest lifetime is coupled to restricted motions in subnanosecond and nanosecond time scales. The overall amplitude of rotation of the indole ring is increased in the membrane-bound conformation of the protein. In reverse micelles, the local dynamics reported by W187 is also considerably increased whereas the overall folding of the protein remains unaffected. The same conformational change of domain III can therefore be provoked by different conditions: calcium binding at high concentration, mild acidic pH [Sopkova, J., Vincent, M., Takahashi, M., Lewit-Bentley, A. , and Gallay, J. (1998) Biochemistry 37, 11962-11970] and the interaction of the protein with the membrane surface. The high flexibility of domain III in the membrane-bound protein suggests that this domain may not be crucial for the interaction of the protein with the membrane, in contrast with previous models. Our data are compatible with atomic force microscopy results which suggest that domain III of annexin V does not interact strongly with the membrane surface [Reviakine, I., Bergma-Schutter, W., and Brisson, A. (1998) J. Struct. Biol. 121, 356-361].

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Section: Discussionsupporting

confidence: 91%

supporting

confidence: 56%

Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

et al. 1999

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“…Previously, Bcl-x L DTM was reported to undergo dimerization although only in the presence of nonionic detergents (Xie et al 1998). Additionally, an oligomeric insertion mechanism is common for many b-barrel toxins (Gouaux 1997;Heuck et al 2001) and the annexin family of proteins (Beermann et al 1998).…”

Section: Resultsmentioning

confidence: 99%

Acid destabilization of the solution conformation of Bcl‐X_L does not drive its pH‐dependent insertion into membranes

Thuduppathy¹,

Hill²

2006

Protein Science

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Regulation of programmed cell death by Bcl-x L is dependent on both its solution and integral membrane conformations. A conformational change from solution to membrane is also important in this regulation. This conformational change shows a pH-dependence similar to the translocation domain of diphtheria toxin, where an acid-induced molten globule conformation in the absence of lipid vesicles mediates the change from solution to membrane conformations. By contrast, Bcl-x L DTM in the absence of lipid vesicles exhibits no gross conformational changes upon acidification as observed by near-and far-UV circular dichroism spectropolarimetry. Additionally, no significant local conformational changes upon acidification were observed by heteronuclear NMR spectroscopy of Bcl-x L DTM. Under conditions that favor the solution conformation (pH 7.4), the free energy of folding for Bcl-x L DTM (DG°) was determined to be 15.8 kcalÁmol. Surprisingly, under conditions that favor a membrane conformation (pH 4.9), DG°was 14.6 kcal Á mol -1. These results differ from those obtained with many other membraneinsertable proteins where acid-induced destabilization is important. Therefore, other contributions must be necessary to destabilize the solution conformation Bcl-x L and favor the membrane conformation at pH 4.9. Such contributions might include the presence of a negatively charged membrane or an electrostatic potential across the membrane. Thus, for proteins that adopt both solution and membrane conformations, an obligatory molten globule intermediate may not be necessary. The absence of a molten globule intermediate might have evolved to protect Bcl-x L from intracellular proteases as it undergoes this conformational change essential for its activity.Keywords: Bcl-2 family; Bcl-x L ; solution to membrane conformational change; diphtheria toxin; pHdependence; pore-forming toxins; protein folding Supplemental material: see www.proteinscience.orgThe Bcl-2 proteins regulate programmed cell death by acting in the cytosol and organellar membranes (Adams and Cory 1998;Chao and Korsmeyer 1998;Green and Reed 1998;Ng and Shore 1998;Harris and Thompson 2000;Hengartner 2000). Some Bcl-2 proteins act by adopting at least two different structural conformations: a solution conformation and an integral membrane conformation. For example, pro-apoptotic Bax is a monomeric, helical bundle protein localized in the cytosol until an apoptotic signal causes translocation to the mitochondrial outer membrane (Suzuki et al. 2000). At the mitochondrial outer membrane, Bax inserts and folds into a large, multimeric integral membrane protein that is thought to regulate the release of cytochrome c Reprint requests to: R. Blake Hill, Department of Biology, The Johns Hopkins University, 3400 N. Charles Street, Baltimore, MD 21218, USA; e-mail: hill@jhu.edu; fax: (702) 441-2490.Abbreviations: TM, transmembrane anchor; NMR, nuclear magnetic resonance; CD, circular dichroism; GdnHCl, guanidine hydrochloride; HSQC, heteronuclear single quantum coherence.Ar...

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“…Among others, the main parameter regulating the calcium-independent binding is the pH value. It has been shown in vitro that annexins A5 and A13b undergo a conformational change at mildly acidic pH (midpoints around pH 4.1 and 5.8, respectively) that resembles that observed after calcium binding (the so-called “open conformation” with exposure of the tryptophan residue located at the AB loop of Domain III) [37,46,47]. These pH values can be reached inside the cell as it is well known that pH can decrease around 1.6 units in the proximity of the membrane in regions rich in anionic phospholipids as PS [48].…”

Section: Annexin Binding To Phospholipid Membranesmentioning

confidence: 99%

Annexin-Phospholipid Interactions. Functional Implications

Lizarbe

Barrasa

Olmo

et al. 2013

IJMS

203

171

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Annexins constitute an evolutionary conserved multigene protein superfamily characterized by their ability to interact with biological membranes in a calcium dependent manner. They are expressed by all living organisms with the exception of certain unicellular organisms. The vertebrate annexin core is composed of four (eight in annexin A6) homologous domains of around 70 amino acids, with the overall shape of a slightly bent ring surrounding a central hydrophilic pore. Calcium- and phospholipid-binding sites are located on the convex side while the N-terminus links domains I and IV on the concave side. The N-terminus region shows great variability in length and amino acid sequence and it greatly influences protein stability and specific functions of annexins. These proteins interact mainly with acidic phospholipids, such as phosphatidylserine, but differences are found regarding their affinity for lipids and calcium requirements for the interaction. Annexins are involved in a wide range of intra- and extracellular biological processes in vitro, most of them directly related with the conserved ability to bind to phospholipid bilayers: membrane trafficking, membrane-cytoskeleton anchorage, ion channel activity and regulation, as well as antiinflammatory and anticoagulant activities. However, the in vivo physiological functions of annexins are just beginning to be established.

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Acid induced equilibrium unfolding of annexin V wild type shows two intermediate states

Cited by 27 publications

References 13 publications

Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

Acid destabilization of the solution conformation of Bcl‐X_L does not drive its pH‐dependent insertion into membranes

Annexin-Phospholipid Interactions. Functional Implications

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Acid induced equilibrium unfolding of annexin V wild type shows two intermediate states

Cited by 27 publications

References 13 publications

Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

Conformational Flexibility of Domain III of Annexin V at Membrane/Water Interfaces

Acid destabilization of the solution conformation of Bcl‐XL does not drive its pH‐dependent insertion into membranes

Annexin-Phospholipid Interactions. Functional Implications

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Acid destabilization of the solution conformation of Bcl‐X_L does not drive its pH‐dependent insertion into membranes