Calorimetric studies of the structural transitions of the human erythrocyte membrane. Studies of the B and C transitions

Surface shape change during fusion of erythrocyte membranes is sensitive to membrane skeleton agents

“…Our results are consistent with an explanation based on WGA-enhanced spectrin-glycophorin binding, because other work (Chasis and Schrier, 1989) implied that binding of WGA to an erythrocyte surface is not likely to cause extracellular cross-linking or lattice formation. pH and ionic strength effects Our observation that a pH of 6.2 or 7.4, instead of 8.5, in the 20 mM NaPi buffer during the heat treatment would block (Table 1, Part D) the heat treatment-induced destabilization of the flat diaphragm is consistent with reports that, compared with a pH of 8.5, pHs from 8.0 to 6.5 cause an increase in the spectrin calorimetric transition by about 2-40C (Brandts et al, 1978). Also, compared with a pH of 8.5 at low ionic strength, it was found (Fig.…”

“…Ralston and Dunbar (1979) showed that spectrin had a thermotropic optical rotary dispersion transition that ranged from -47 to 49°C at 0.1 M NaCl but from -37 to 50°C at 0.005 M NaCl. Brandts et al (1978) reported an analogous ionic strength dependence for the spectrin calorimetric transition, but the effect was weaker and the data were obtained over a much narrower ionic strength range. They also reported that, compared with a pH of 8.5, pHs from 8.0 to 6.5 cause an increase in the spectrin calorimetric transition by about 2-4°C (Brandts et al, 1978).…”

“…Brandts et al (1978) reported an analogous ionic strength dependence for the spectrin calorimetric transition, but the effect was weaker and the data were obtained over a much narrower ionic strength range. They also reported that, compared with a pH of 8.5, pHs from 8.0 to 6.5 cause an increase in the spectrin calorimetric transition by about 2-4°C (Brandts et al, 1978). Also, it has been reported that lower pHs increase the band 3-ankyrin association (Low et al, 1991).…”

Autotomic Behavior of the Propeptide in Propeptide-mediated Folding of Prosubtilisin E

“…Although independent unfolding of different domains in proteins is not a common event, it has been observed in several proteins, including immunoglobulin G, 24 the α-subunit of bacterial luciferase, 25 aspartate transcarbamoylase of Escherichia coli, 26 and band 3 of human RBC membrane. 27 It has also been shown that by changing the solution conditions, [26][27][28] or introducing mutations within one of the domains, 29 one can modulate unfolding transitions. Mutations within the hinge region of yeast phosphoglycerate kinase resulted in two overlapping transitions with T m values of 45 and 54°C, respectively, in contrast with one asymmetric transition at 54°C observed in the DSC scan of the WT.…”

Calorimetric measurements of the effect of 330‐MHz radiofrequency radiation on human erythrocyte ghosts

“…Each of the many peaks is believed to be due to a localized structural transition induced by thermal stress. The origins of these transitions are discussed in detail elsewhere [Brandts et al, 1977;Brandts et al, 1978;Snow et al, 19781. The A-transition (maximum at approximately 46 "C) in the main corresponds to the thermal inactivation of spectrin.…”