Membrane Surface-Charge Titration Probed by Gramicidin A Channel Conductance

Rostovtseva, Tatiana K.; Aguilella, Vicente M.; Vodyanoy, Igor; Bezrukov, Sergey M.; Parsegian, V. Adrian

doi:10.1016/s0006-3495(98)77620-9

Cited by 96 publications

(133 citation statements)

References 35 publications

(45 reference statements)

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“…Actually the single-channel conductance of gramicidin A in 1 M CsCl is higher by 30% in the anionic phophatidylserine membrane as compared with that in neutral phosphatidylcholine membrane (81,82). However, Aguilella and Bezrukov (83) have shown that the variation in the lipid surface charge does not change the conductance of alamethicin channels in 1 M NaCl.…”

Section: Two Conductance States Of the Colicin E1 Channel: A "Giant" mentioning

confidence: 96%

Lipid Dependence of the Channel Properties of a Colicin E1-Lipid Toroidal Pore

Sobko

Kotova

Antonenko

et al. 2006

Journal of Biological Chemistry

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Colicin E1 belongs to a group of bacteriocins whose cytotoxicity toward Escherichia coli is exerted through formation of ion channels that depolarize the cytoplasmic membrane. The lipid dependence of colicin single-channel conductance demonstrated intimate involvement of lipid in the structure of this channel. The colicin formed "small" conductance 60-picosiemens (pS) channels, with properties similar to those previously characterized, in 1,2-dieicosenoyl-snglycero-3-phosphocholine (C20) or thinner membranes, whereas it formed a novel "large" conductance 600-pS state in thicker 1,2-dierucoyl-sn-glycero-3-phosphocholine (C22) bilayers. Both channel states were anion-selective and voltage-gated and displayed a requirement for acidic pH. Lipids having negative spontaneous curvature inhibited the formation of both channels but increased the ratio of open 600 pS to 60 pS conductance states. Different diameters of small and large channels, 12 and 16 Å , were determined from the dependence of single-channel conductance on the size of nonelectrolyte solute probes. Colicin-induced lipid "flip-flop" and the decrease in anion selectivity of the channel in the presence of negatively charged lipids implied a significant contribution of lipid to the structure of the channel, most readily described as toroidal organization of lipid and protein to form the channel pore.The lipid environment of membrane proteins that defines the local distribution of polarity, dielectric constant, and steric geometry has a central role in the determination of protein structure and function. For ion channels, lipids impose the following constraints: (i) structure-function is sensitive to the matching of hydrophobic thickness of the protein and lipid bilayer (1-10); (ii) opening of channels (e.g. mechano-sensitive, can be dependent on bilayer tension) (11), which manifests itself in a dependence on acyl chain length (12); (iii) spontaneous curvature (SC) 2 of lipids linked to the lateral pressure of the bilayer can modulate ion channel activity (13), as demonstrated for the KcsA channel (14) and mechano-sensitive MscL channels (12, 15); and (iv) many channel proteins require anionic lipids for function (16 -19).Channel-forming proteins can require specific lipids, presumably because of a combination of charge and curvature parameters, to form active channels (e.g. anionic lipid bound between the transmembrane ␣-helices and necessary for gating of the KcsA channel (20, 21)). The lantibiotic nisin provides a well defined example of lipid participation in peptide pore formation, in which the peptidoglycan precursor lipid II is an intrinsic component of the pore formed by this antimicrobial peptide (22). The proposed structure of this pore contains 5-8 nisin molecules and an identical number of lipid II molecules (23). Participation of lipid in the formation of a channel wall was hypothesized for cholesteroldependent cytolysins (24,25).Colicins are plasmid-encoded bacteriocins that are cytotoxic to Escherichia coli and related strains. Their modes of ...

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Section: Two Conductance States Of the Colicin E1 Channel: A "Giant" mentioning

confidence: 96%

Lipid Dependence of the Channel Properties of a Colicin E1-Lipid Toroidal Pore

Sobko

Kotova

Antonenko

et al. 2006

Journal of Biological Chemistry

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“…A similar enhancement of the conductance for gramicidin channels has been reported in lipid membranes of diphytanoyl phophatidylserine (PS). 20,21 On the other hand, the membrane surface charges did not affect the lifetime of the channel events, except for the DOPS bilayer, where short-lifetime events appeared to a lesser extent.…”

Section: Effect Of Membrane Surface Chargesmentioning

confidence: 89%

“…[8][9][10] The formation of the gramicidin dimer is associated with a local stress of the bilayer structure caused by the thickness of hydrocarbon region of a PC bilayer. 11 The kinetics of dimer formation is modulated by the membrane thickness, 10,[12][13][14][15][16][17][18][19] the charges of the lipid head groups, 20,21 the chemical structures of the head groups, 22 the structure of hydrophobic tails, 15,23 and the cholesterol concentration. 24 Such regulation of the gramicidin function by the bilayer physical properties is discussed extensively in a recent review.…”

Section: Introductionmentioning

confidence: 99%

Planar Lipid Bilayers Containing Gramicidin A as a Molecular Sensing System Based on an Integrated Current

2012

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“…For instance, cation channel conductance increases in negatively charged membranes due to the accumulation of cations within the Gouy-Chapman Layer. (23) Elec-tric fields can project further and exist in the bulk volume of the EICS where they may influence transport kinetics of solutes and neighboring cells. (24,25) Within the boundary layers associated with the glycocalyx the structure of water itself can affect the movement of ions.…”

Section: J= -D φmentioning

confidence: 99%

Windows to cell function and dysfunction: Signatures written in the boundary layers

Smith¹,

Collis²,

Messerli³

2010

BioEssays

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The medium surrounding cells either in culture or in tissues contains a chemical mix varying with cell state. As solutes move in and out of the cytoplasmic compartment they set up characteristic signatures in the cellular boundary layers. These layers are complex physical and chemical environments whose profiles both reflect cell physiology and provide conduits for intercellular messaging. Here we review some of the most relevant characteristics of the extracellular/intercellular space. Our initial focus is primarily with cultured cells but we extend our consideration to the far more complex environment of tissues and discuss how chemical signatures in the boundary layer can or may affect cell function. Critical to the entire essay are the methods used, or being developed, to monitor chemical profiles in the boundary layers. We review recent developments in ultramicro electrochemical sensors and tailored optical reporters suitable for the task 20 in hand. IntroductionThe advent of electron tomography with 3 dimensional image reconstruction has revealed a fundamental beauty and complexity behind the structure of the living cell. Notable contributions have come from several imaging laboratories but one of the most compelling can be found in Marsh et al.(1) From such reconstructions the complexity within a cell is quite staggering and in the 4 th dimension of time this entire structure is in motion. The question that becomes extremely interesting is how molecular and ionic signals are regulated and move within these matrices, where chemical diffusion will be significantly altered. (2) However, complexity, both structural and functional, does not stop at the plasma membrane but extends outwards 30 into the extracellular/intercellular space (EICS: Fig.1). The chemical dynamics within this space are hypothesized to play key roles in cancer, spreading depression, epilepsy and sleep disorders. (3)(4)(5)(6) The purpose of this essay is to consider what we can learn from this space and the methods for following the dynamics of chemical movement within the diffusive boundary layers that comprise an integral part of a cell. We will start by noting the physical and chemical features involved.

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Membrane Surface-Charge Titration Probed by Gramicidin A Channel Conductance

Cited by 96 publications

References 35 publications

Lipid Dependence of the Channel Properties of a Colicin E1-Lipid Toroidal Pore

Lipid Dependence of the Channel Properties of a Colicin E1-Lipid Toroidal Pore

Planar Lipid Bilayers Containing Gramicidin A as a Molecular Sensing System Based on an Integrated Current

Windows to cell function and dysfunction: Signatures written in the boundary layers

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