Wu, J, Voss, J, Hubbell, W L, Kaback, H R
Site-directed chemical cleavage of lactose permease indicates that helix V is in close proximity to helices VII and VIII. To test this conclusion further, permease containing a biotin-acceptor domain...
Voss, J, Salwiński, L, Kaback, H R, Hubbell, W L
The use of molecular genetics to introduce both a metal ion binding site and a nitroxide spin label into the same protein opens the use of paramagnetic metalnitroxyl interactions to estimate...
Voss, J, Hubbell, W L, Kaback, H R
As shown in the accompanying paper, the magnetic dipolar interaction between site-directed metal-nitroxide pairs can be exploited to measure distances in T4 lysozyme, a protein of known structure. To...
Altenbach, C, Greenhalgh, D A, Khorana, H G, Hubbell, W L
Ten mutants of bacteriorhodopsin, each containing a single cysteine residue regularly spaced along helix D and facing the lipid bilayer, were derivatized with a nitroxide spin label. Collision rates...
Greenhalgh, D A, Altenbach, C, Hubbell, W L, Khorana, H G
The amino acids Asp-96, Asp-85, and Arg-82, which are important for proton transport by bacteriorhodopsin, are located in helix C. Site-directed spin labeling has been used to map their positions...
Stability of "salt bridges" in membrane proteins.
We estimate the free energies of transfer of ionized amino acid side chains in water to both their ion-paired and neutral hydrogen-bonded states in low-dielectric media. The difference between the...
Site-specific incorporation of biophysical probes into proteins.
Cornish, V W, Benson, D R, Altenbach, C A, Hideg, K, Hubbell, W L, Schultz, P G
Biophysical probes which can detect structural changes in proteins and the interaction of proteins with other macromolecules are important tools in studying protein function. Many difficulties...
We present a method to simulate electron paramagnetic resonance spectra of spin-labeled proteins that explicitly includes the protein structure in the vicinity of the attached spin label. The method...
A new general method for the determination of electrostatic potentials at biological surfaces is presented. The approach is based on measurement of the collision frequency of a charged nitroxide in...
Franklin, J C, Cafiso, D S, Flewelling, R F, Hubbell, W L
Two spin-labeled derivatives of the hydrophobic anion trinitrophenol have been synthesized and characterized in lipid vesicles. In the presence of lipid vesicles, the electron paramagnetic resonance...
Altenbach, C, Froncisz, W, Hyde, J S, Hubbell, W L
Melittin spin-labeled specifically with a nitroxide at positions 7, 21, 23, or the amino terminus was bound to phospholipid membranes, and the exposure of the spin label to the aqueous phase was...
Distribution of charge on photoreceptor disc membranes and implications for charged lipid asymmetry.
Tsui, F C, Sundberg, S A, Hubbell, W L
A novel spin labeling technique is used to determine both the inner and outer surface potentials of isolated rod outer segment disc membranes and of reconstituted membranes containing rhodopsin with...
An equilibrium transmembrane asymmetry in charged lipids is shown to arise as a result of oriented, bipolar proteins in the membrane. The basic interaction giving rise to the asymmetry is between a...
A multifrequency electron spin resonance study of T4 lysozyme dynamics.
Barnes, J P, Liang, Z, Mchaourab, H S, Freed, J H, Hubbell, W L
Electron spin resonance (ESR) spectroscopy at 250 GHz and 9 GHz is utilized to study the dynamics and local structural ordering of a nitroxide-labeled enzyme, T4 lysozyme (EC 3.2.1.17), in aqueous...
Light-induced interfacial potentials in photoreceptor membranes.
A rapid change in an interfacial electric potential of isolated bovine rod outer segment disk membranes occurs upon illumination. This potential change, which has been detected by the use of...
Transmembrane electrical currents of spin-labeled hydrophobic ions.
When spin-labeled phosphonium ions are rapidly mixed with phospholipid vesicles, time-dependent changes in the electron paramagnetic resonance spectrum of the spin label are observed. These changes...
Tsui, F C, Ojcius, D M, Hubbell, W L
Potentiometric titrations and surface potential measurements have been used to determine the intrinsic pKa values of both the carboxyl and amino groups of phosphatidylserine (PS) in mixed vesicles of...
The thermodynamic properties for the interaction of the hydrophobic ion tetraphenylphosphonium (TPP+) with egg phosphatidylcholine vesicles were studied in detail by equilibrium dialysis and spin...
The total potential energy profile for hydrophobic ion interactions with lipid bilayers can be written as the sum of four terms: the electrical Born, image and dipole contributions, and a neutral...
In earlier work, Castle and Hubbell (1976) demonstrated the use of a spin-labeled amphiphile as a probe for the electrostatic potential at the outer surface of charged phospholipid vesicles. In...
Electrogenic H+/OH- movement across phospholipid vesicles measured by spin-labeled hydrophobic ions.
Transmembrane pH gradients created across phospholipid vesicles give rise to time-dependent potentials as determined from the EPR spectra of phosphonium ion spin labels in the system. From the...
Wu, J, Voss, J, Hubbell, W L, Kaback, H R
Site-directed chemical cleavage of lactose permease indicates that helix V is in close proximity to helices VII and VIII. To test this conclusion further, permease containing a biotin-acceptor domain...
Voss, J, Salwiński, L, Kaback, H R, Hubbell, W L
The use of molecular genetics to introduce both a metal ion binding site and a nitroxide spin label into the same protein opens the use of paramagnetic metalnitroxyl interactions to estimate...
Voss, J, Hubbell, W L, Kaback, H R
As shown in the accompanying paper, the magnetic dipolar interaction between site-directed metal-nitroxide pairs can be exploited to measure distances in T4 lysozyme, a protein of known structure. To...
Altenbach, C, Greenhalgh, D A, Khorana, H G, Hubbell, W L
Ten mutants of bacteriorhodopsin, each containing a single cysteine residue regularly spaced along helix D and facing the lipid bilayer, were derivatized with a nitroxide spin label. Collision rates...
Greenhalgh, D A, Altenbach, C, Hubbell, W L, Khorana, H G
The amino acids Asp-96, Asp-85, and Arg-82, which are important for proton transport by bacteriorhodopsin, are located in helix C. Site-directed spin labeling has been used to map their positions...
Stability of "salt bridges" in membrane proteins.
We estimate the free energies of transfer of ionized amino acid side chains in water to both their ion-paired and neutral hydrogen-bonded states in low-dielectric media. The difference between the...
Site-specific incorporation of biophysical probes into proteins.
Cornish, V W, Benson, D R, Altenbach, C A, Hideg, K, Hubbell, W L, Schultz, P G
Biophysical probes which can detect structural changes in proteins and the interaction of proteins with other macromolecules are important tools in studying protein function. Many difficulties...
We present a method to simulate electron paramagnetic resonance spectra of spin-labeled proteins that explicitly includes the protein structure in the vicinity of the attached spin label. The method...
A new general method for the determination of electrostatic potentials at biological surfaces is presented. The approach is based on measurement of the collision frequency of a charged nitroxide in...
Franklin, J C, Cafiso, D S, Flewelling, R F, Hubbell, W L
Two spin-labeled derivatives of the hydrophobic anion trinitrophenol have been synthesized and characterized in lipid vesicles. In the presence of lipid vesicles, the electron paramagnetic resonance...
Altenbach, C, Froncisz, W, Hyde, J S, Hubbell, W L
Melittin spin-labeled specifically with a nitroxide at positions 7, 21, 23, or the amino terminus was bound to phospholipid membranes, and the exposure of the spin label to the aqueous phase was...
Distribution of charge on photoreceptor disc membranes and implications for charged lipid asymmetry.
Tsui, F C, Sundberg, S A, Hubbell, W L
A novel spin labeling technique is used to determine both the inner and outer surface potentials of isolated rod outer segment disc membranes and of reconstituted membranes containing rhodopsin with...
An equilibrium transmembrane asymmetry in charged lipids is shown to arise as a result of oriented, bipolar proteins in the membrane. The basic interaction giving rise to the asymmetry is between a...
A multifrequency electron spin resonance study of T4 lysozyme dynamics.
Barnes, J P, Liang, Z, Mchaourab, H S, Freed, J H, Hubbell, W L
Electron spin resonance (ESR) spectroscopy at 250 GHz and 9 GHz is utilized to study the dynamics and local structural ordering of a nitroxide-labeled enzyme, T4 lysozyme (EC 3.2.1.17), in aqueous...
Light-induced interfacial potentials in photoreceptor membranes.
A rapid change in an interfacial electric potential of isolated bovine rod outer segment disk membranes occurs upon illumination. This potential change, which has been detected by the use of...
Transmembrane electrical currents of spin-labeled hydrophobic ions.
When spin-labeled phosphonium ions are rapidly mixed with phospholipid vesicles, time-dependent changes in the electron paramagnetic resonance spectrum of the spin label are observed. These changes...
Tsui, F C, Ojcius, D M, Hubbell, W L
Potentiometric titrations and surface potential measurements have been used to determine the intrinsic pKa values of both the carboxyl and amino groups of phosphatidylserine (PS) in mixed vesicles of...
The thermodynamic properties for the interaction of the hydrophobic ion tetraphenylphosphonium (TPP+) with egg phosphatidylcholine vesicles were studied in detail by equilibrium dialysis and spin...
The total potential energy profile for hydrophobic ion interactions with lipid bilayers can be written as the sum of four terms: the electrical Born, image and dipole contributions, and a neutral...
In earlier work, Castle and Hubbell (1976) demonstrated the use of a spin-labeled amphiphile as a probe for the electrostatic potential at the outer surface of charged phospholipid vesicles. In...
Electrogenic H+/OH- movement across phospholipid vesicles measured by spin-labeled hydrophobic ions.
Transmembrane pH gradients created across phospholipid vesicles give rise to time-dependent potentials as determined from the EPR spectra of phosphonium ion spin labels in the system. From the...
Structure in the channel forming domain of colicin E1 bound to membranes: the 402-424 sequence.
To explore the structure of the pore-forming fragment of colicin E1 in membranes, a series of 23 consecutive single cysteine substitution mutants was prepared in the sequence 402-424. Each mutant was...
Protein global fold determination using site-directed spin and isotope labeling.
Gaponenko, V., Howarth, J. W., Columbus, L., Gasmi-Seabrook, G., Yuan, J., Hubbell, W. L., ...
We describe a simple experimental approach for the rapid determination of protein global folds. This strategy utilizes site-directed spin labeling (SDSL) in combination with isotope enrichment to...