Characterization of thermotropic structural transitions of the erythrocyte membrane: A biochemical and electron‐paramagnetic resonance approach

Abstract

The relationship between membrane structural properties and functions has been generally inferred from observed thermotropic phenomena. By the use of 16-dinyloxyl stearic acid spin probe we investigated the red blood cell membrane components involved in three characteristic thermotropic structural transitions occurring at 8, 20, and 40 degrees C. The transition at 8 degrees C is removed by chymotrypsin treatment at the cytoplasmic membrane layer. The 20 degrees C phase transition is unmodified after chymotrypsin treatment and occurs at 15 degrees C after complete proteolysis of intramembrane chymotrypsin-insensitive peptides. Liposomes from the total lipid extract of RBC show only one thermotropic transition at 15 degrees C. The 40 degrees C phase transition is absent in vesicles free of skeletal proteins, in vesicles obtained after RBC storage, and in low-ionic-strength resealed ghosts. Transitions at 8 degrees C and 40 degrees C appear to be due to the interactions of cytoplasmic exposed proteins with membrane, whereas the 20 degrees C transition is intrinsic to the lipid component.

The dependence on external cation of sodium and potassium fluxes across the human red cell membrane at low temperatures.

“…Some methods, e.g. Raman spectroscopy (Verma & Wallach, 1976), 31P-nuclear magnetic resonance (Cullis, 1976), and viscometry (Zimmer & Schirmer, 1974) reveal discontinuities in human red cell membrane ordering at about 15-20 TC, while electron paramagnetic resonance (Minetti, Ceccarini & di Stasi, 1984) shows discontinuities at 8, 20 and 40 'C. Trauble & Eibl (1974) showed that phase transitions in simple phospholipid systems can be modified by pH and divalent cations, but in general, the divalents (or decreasing pH) increase the temperature of phase transition (e.g.…”

Role of membrane thermotropic properties on hypotonic hemolysis and hypertonic cryohemolysis of human red blood cells

“…To check with more accuracy the effect of chlorpromazine on the 20°C break, we used cytoplasmic chymotrypsin-digested RBC. As reported in Figure 2 of the accompanying paper [6], this treatment effaces the protein-dependent 8°C break but maintains the 20°C break virtually unmodified. These membranes, after chlorpromazine treatment, show one break at 15°C (data not shown).…”

“…The presence of these transitions suggests a heterogeneous distribution of membrane components, but *H NMR results seem to exclude the presence of extended lateral phase separations between membrane components (see [29] and discussion of the accompanying paper [6]). The physical changes involved in the thermotropic breaks are unknown, but there is general agreement that they arise from thermotropic structural changes at the level of lipid or protein-lipid areas [6,.…”

“…The spectra of 16-DSA in anisotropic membranes, can be evaluated by measuring the amplitude ratio of lines ho and h-I as an empirical fluidity index (see results and discussion of the accompanying paper [6]). In Figure 6 the plot of log (ho/hkl) against the reciprocal of temperature for RBC and for RBC submitted to different treatments is shown.…”

In Vitro Effects of Colchicine on Human Erythrocyte Membranes: An ESR Study

“…Structural transitions in the 0 -5 0 °C tem perature range of the erythrocyte cell m em brane has been reported using a variety of physicochemical techniques (Nigg and Cherry, 1979;Galla and Luisetti, 1980;Minetti et al, 1984) but structural changes involved in these transitions are still unclear. However, noteworthy is the lat eral mobility of glycoproteins which changes dis-continuously with tem perature (Forte et al, 1985;Nigg and Cherry, 1979) and appears to be con trolled by skeletal proteins (Golan and Weatch, 1980).…”