Human spectrin. I. A classical light scattering study

Elgsaeter, Arnljot

doi:10.1016/0005-2795(78)90069-7

Cited by 53 publications

(21 citation statements)

References 23 publications

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“…The axial ratio of the equivalent hydrodynamic ellipsoid of revolution is then 10 (as against 13 for an unhydrated particle). This high degree of asymmetry in solution agrees with expectation from the electron microscope images of the negatively stained fragment [Imamura et al, 19881 and with the conformational character of spectrin [Elgsaeter, 1978;Reich et al, 19821.…”

Section: Methodssupporting

confidence: 88%

Properties of the spectrin‐like structural element of smooth‐muscle α‐actinin

Kahana

Gratzer

1991

Cell Motil. Cytoskeleton

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The fragment of smooth muscle alpha-actinin, comprising the four spectrin-like structural repeating units, has a high alpha-helix content, similar to that of spectrin, and a hydrodynamic frictional coefficient, indicative of an elongated, probably bent or kinked rod-like structure, as found for spectrin dimer and tetramer. The fragment exists in solution as an extremely stable dimer, which is dissociated only under denaturing conditions and is much more resistant to dissociation by urea than is the spectrin heterodimer. High-resolution proton magnetic resonance spectra reveal that a part of the polypeptide chain gives rise to sharp resonances; this is also true of spectrin and it implies that the individual structural repeating units contain segmentally mobile elements, which may be required to generate the elastic properties of the spectrin family of proteins. Again like spectrin, the alpha-actinin fragment contains multiple binding sites for long-chain fatty acids, as revealed by quenching of tryptophan fluorescence by 2-bromostearate (though not by 9(10)-bromostearate). The results point to extensive structural and functional similarities between the repeating units of all the proteins of the spectrin family.

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Section: Methodssupporting

confidence: 88%

Properties of the spectrin‐like structural element of smooth‐muscle α‐actinin

Kahana

Gratzer

1991

Cell Motil. Cytoskeleton

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“…The expansion and stiffening of spectrin at low ionic strength both in the isolated form and in situ has been reported by several workers [Elgsaeter, 1978;Mikkelsen and Elgsaeter, 1978;Sandvold et al, 1989;Shotton et al 1979;McGough and Josephs, 19901. We determined the nature and extent of the change in the tryptophan environment, as reflected by its fluorescence, due to lowering the ionic strength.…”

Section: Effect Of Low Ionic Strengthmentioning

confidence: 78%

Fluorescence studies of spectrin and its subunits

Subbarao

MacDonald

1994

Cell Motil. Cytoskeleton

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To better understand the solution structure of spectrin, the environment of its tryptophan residues have been examined by fluorescence spectroscopy. The spectra and the extent of quenching by several quenching agents have been determined for intact spectrin and its alpha and beta subunits. The arsenal of quenchers used in the study represented both hydrophilic and hydrophobic species including anionic, cationic and neutral compounds. Effects on spectrin fluorescence of ethanol and ionic strength, which extend and/or rigidify spectrin, and of glycerol, which is commonly used in electron microscopy of the protein, have also been assessed in the presence and absence of quenchers. Most of the tryptophans of spectrin are either internally quenched or are sequestered, hindering the approach of hydrophilic quenching agents. Both the spectral shape and the extent of quenching by acrylamide indicate that some tryptophans of the beta subunit are slightly more exposed in the isolated chain than in the dimer. Similar effects on spectra and on quenching of the intact dimer and of the isolated beta chain are seen when the ionic strength is reduced. Ethanol and glycerol reduce spectrin tryptophan accessibility to 2-p-toluidinyl napthalene-6-sulfonic acid (TNS). It therefore appears that low ionic strength, alpha-beta association and neutral solute (or lowered dielectric constant) all induce a similar, but modest conformational change in the domain structure. The extent of TNS binding is not increased by lowering the ionic strength, suggesting that the expansion and/or stiffening of the molecule in low electrolyte solution does not involve exposure of significant numbers of hydrophobic sites.

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“…From the work of Tyler, Shotten and Branton [62,66] macromolecules, and there is no reason to suspect artifactual changes in the morphology of the molecules, it will be important to confirm this structure using other techniques and on preparations prepared in different ways. Some indication that this flexible rod model is probably close to reality has been provided by some recent light scattering experiments [14] and by the results of controlled proteolytic digestion experiments 3.…”

Section: Fig 2 Spectrin Dimer (A) and Tetramer (B)mentioning

confidence: 93%

“…Spectrin isolated from red cell ghost membranes by suspending the membranes in dilute buffers containing EDTA at 37 ~ is largely composed of a dimer form with a tool wt of approximately 450,000, and this form appears to be a flexible rod of approximately 1,000 ~ in length. When spectrin is prepared by extracting ghost membranes at low temperatures, for Elgsaeter, 1978 [14] S2oW of monomer 5.5 S in deoxycholate S2oW of dimer 6.0 S Mol wt of dimer by sedimentation equilibrium 500,000 Assuming monomer and dimer are both cylindrical rods, dimensions calculated to be 24A x 830]~ (monomer) 24A x 1660A (dimer) S2oW of dimers and tetramers found to be 8.5 S and 12 S Mol wt of tetramer ~ 1,000,000 Hydrodynamic properties suggest a highly expanded but basically symmetrical molecule of stokes radium 200A $2o W of dimer 9.5 S Mol wt of dimer ~ 500,000 Axial Ratio ~ ~10 Radium of gyration ~ 80~, (upper limit) Electron microscopy of negatively stained preparations suggest dimer is a compact, slightly elongated unit tetramer probably two parallel dimers Electron micrographs of low angle shadowed dimers show flexible rods 1,000A long; 12 S tetramers appear as 2,000A rods Light scattering measurements of dimers indicate a radius of gyration 400N, suggesting that isolated spectrin dimers are flexible rods the lengths of which are in the 760A to 1,400~ range…”

Section: The Spectrin Tetramer Appears To Be a Flexible Rodmentioning

confidence: 99%

Spectrin: Present status of a putative cyto-skeletal protein of the red cell membrane

Marchesi

1979

J. Membrain Biol.

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Human spectrin. I. A classical light scattering study

Cited by 53 publications

References 23 publications

Properties of the spectrin‐like structural element of smooth‐muscle α‐actinin

Properties of the spectrin‐like structural element of smooth‐muscle α‐actinin

Fluorescence studies of spectrin and its subunits

Spectrin: Present status of a putative cyto-skeletal protein of the red cell membrane

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