Dielectric relaxations on erythrocyte membrane as revealed by spectrin denaturation

Ivanov, Ivan T.; Paarvanova, Boyana

doi:10.1016/j.bioelechem.2016.03.007

Cited by 15 publications

(30 citation statements)

References 66 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6, the -ΔZ im vs. ΔZ re plot at the spectrin denaturation temperature revealed only one dielectric relaxation due to the direct interaction of electric field with the dipole moments of spectrin Ivanov and Paarvanova 2016). This finding is consistent with the basic conception that Triton-X-100 residues lacked closed lipid bilayer encapsulating them.…”

Section: Dielectric Relaxations On Spectrin and Band 3 Of Triton-x-10supporting

confidence: 78%

“…For example, at 120 mM NaCl, this critical frequency was decreased from 9 MHz at zero % glycerol to about 5 MHz at 40% glycerol (not shown). These data are in full concert with the same dependences, recently reported for the spectrin skeleton of intact erythrocytes and impermeable EGMs (Ivanov and Paarvanova 2016) and indicate preserved molecular structure and dynamics of membrane skeleton in Triton-X-100 shells.…”

Section: Dielectric Relaxations On Spectrin and Band 3 Of Triton-x-10supporting

confidence: 74%

“…5) indicating that dielectrically active segments of spectrin increased their mobility after the spectrin denaturation. Previous study (Ivanov and Paarvanova 2016) reported that the change of the capacitance (dielectric polarizability) of intact erythocytes and impermeable EGMs at the spectrin denaturation temperature (49.5°C) depended on frequency; it decreased at low frequencies (50 kHz-3 MHz) and increased at higher frequencies (3-10 MHz). This frequency effect was explained by the adherence of a part of denatured spectrin to the encapsulating lipid bilayer resulting in partial immobilization of dielectrically active spectrin segments and hardening of erythrocyte plasma membrane.…”

Section: Discussionmentioning

confidence: 99%

“…Peaks A and C exhibit the heat denaturation of spectrin and anion exchanger, respectively. each Triton-X-100 shell represented a network of proteins devoid of closed lipid bilayer surrounding them and, in contrast to intact erythrocytes and their resealed EGMs (Ivanov and Paarvanova 2016) it was fully transparent to the incident electric field with any frequency from the indicated frequency interval.…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies Ivanov and Paarvanova 2016) have noted changes in the dielectric properties (complex impedance, Z*; complex capacitance, C*; dielectric loss curve) of human erythrocytes and their isolated impermeable EGMs and Triton-X-100 shells, induced at the spectrin denaturation temperature (49.5°C). Based on the temperature dependence of the loss curve, the spectrin skeleton of EGMs was considered dielectrically active only at native state.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of heat and freeze on isolated erythrocyte submembrane skeletons

Ivanov¹,

Paarvanova²,

Ivanov³

et al. 2017

gpb

View full text Add to dashboard Cite

Abstract. In this study we heated insoluble residues, obtained after Triton-X-100 (0.1 v/v%) extraction of erythrocyte ghost membranes (EGMs). Specific heat capacity, electric capacitance and resistance, and optical transmittance (280 nm) sustained sharp changes at 49°C (T A ) and 66°C (T C ), the known denaturation temperatures of spectrin and band 3, respectively. The change at T A was selectively inhibited by diamide (1 mM) and taurine mustard (1 mM) while its inducing temperature was selectively decreased by formamide in full concert with the assumed involvement of spectrin denaturation. In the residues of EGMs, pretreated with 4,4'-diiso-thiocyanato stilbene-2,2'-disulfonic acid (DIDS), the change at T C was shifted from 66 to 78°C which indicated the involvement of band 3 denaturation. The freeze and rapid thaw of EGM residues resulted in a strong reduction of cooperativity of band 3 denaturation while the slow thaw completely eliminated the peak of this denaturation. These effects of freeze-thaw were prevented in residues obtained from DIDS-treated EGMs. The freeze-thaw of residues slightly affected spectrin denaturation at 49°C although an additional denaturation appeared at 55°C. The results indicate preserved molecular structure and dynamics of the membrane skeleton in Triton-X-100 extracts of EGMs. The freeze-thaw inflicted strong damage on band 3 and spectrin-actin skeleton of EGM extracts which is relevant to cryobiology, cryosurgery and cryopreservation of cells.

show abstract

Section: Dielectric Relaxations On Spectrin and Band 3 Of Triton-x-10supporting

confidence: 78%

Section: Dielectric Relaxations On Spectrin and Band 3 Of Triton-x-10supporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of heat and freeze on isolated erythrocyte submembrane skeletons

Ivanov¹,

Paarvanova²,

Ivanov³

et al. 2017

gpb

View full text Add to dashboard Cite

show abstract

Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes

Ivanov,

Paarvanova

2023

Bioelectromagnetics

View full text Add to dashboard Cite

Band 3 protein and glycophorin C are the two major integral proteins of the lipid membrane of human red blood cells (RBCs). They are attached from below to a network of elastic filamentous spectrin, the third major RBC membrane protein. The binding properties of the attachments to spectrin affect the shape and deformability of RBCs. We addressed band 3 and glycophorin C attachments to spectrin by measuring the strength of two recently discovered radiofrequency dielectric relaxations, βsp (1.4 MHz) and γ1sp (9 MHz), that are observable as changes in the complex admittance of RBCs in medium. In medium at pH 5.2, and also in media with protic substances (formamide, methylformamide, or urea), the βsp relaxation became inhibited that is attributable to detachment of glycophorin C from spectrin. In medium at pH 9.2, we observed inhibition of γ1sp relaxation attributable to detachment of band 3 from spectrin, as also was seen in media with aprotic substances difluoropyridine, dimethylsolfoxide, dimethylformamide, acetone, sodium tetrakis(4‐fluorophenyl)borate), chlorpromazine, thioridazine and trifluopiperazine. The viscogenic cosolvents (glycerol, ethylene glycol, or i‐erythritol) inhibited both the βsp and γ1sp relaxations and significantly lowered their characteristic frequencies. Our observations indicate that the glycophorin C attachment to spectrin has nucleophilic centers whose saturation disconnects this attachment and inhibits the βsp relaxation, whereas at band 3‐spectrin attachment site, it is the saturation of electrophilic centers that weakens this attachment and inhibits the γ1sp relaxation.

show abstract

Differential dielectroscopic data on the relation of erythrocyte membrane skeleton to erythrocyte deformability and flicker

Ivanov

Paarvanova

2021

Eur Biophys J

View full text Add to dashboard Cite

Dielectric relaxations on erythrocyte membrane as revealed by spectrin denaturation

Cited by 15 publications

References 66 publications

Effects of heat and freeze on isolated erythrocyte submembrane skeletons

Effects of heat and freeze on isolated erythrocyte submembrane skeletons

Radiofrequency dielectric spectroscopy study: Effects of pH, hydrogen bond donors and acceptors on the attachment of spectrin skeleton to the lipid membrane of erythrocytes

Differential dielectroscopic data on the relation of erythrocyte membrane skeleton to erythrocyte deformability and flicker

Contact Info

Product

Resources

About