Human erythrocyte spectrin dimer intrinsic viscosity: temperature dependence and implications for the molecular basis of the erythrocyte membrane free energy

• Published in: Biochimica et biophysica acta Vol. 816; no. 1; pp. 102 - 110
• Main Authors: STOKKE, B. T, MIKKELSEN, A, ELGSAETER, A
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier 11.06.1985; North-Holland
• Subjects: Biological and medical sciences; Erythrocyte Membrane - metabolism; Fundamental and applied biological sciences. Psychology; Humans; Macromolecular Substances; Mathematics; Models, Chemical; Molecular biophysics; Physico-chemical properties of biomolecules; Spectrin - analysis; Temperature; Thermodynamics; Viscosity; Human; Spectrin; Membrane protein; Temperature; Shear modulus; Intrinsic viscosity; Plasma membrane; Red blood cell; Persistence length; Dimer; Flexibility; Solution
• ISSN: 0006-3002; 1878-2434
• DOI: 10.1016/0005-2736(85)90398-0

We have determined experimentally the temperature dependence of human erythrocyte spectrin dimer intrinsic viscosity at shear rates 8-12 s-1 using a Cartesian diver viscometer. We find that the intrinsic viscosity decreases from 43 +/- 3 ml/g at 4 degrees C to 34 +/- 3 ml/g when the temperature is increased to 38 degrees C. Our results show that spectrin dimers are flexible worm-like macromolecules with persistence length about 20 nm and that the mean square end-to-end distance for this worm-like macromolecules decreases when the temperature is increased. This implies that the spectrin dimer internal energy decreases when the end-to-end distance is increased and that the free energy increase associated with making the end-to-end distance longer than the equilibrium value for the free molecules is of entropic origin. The temperature dependence of the erythrocyte membrane shear modulus reported previously in the literature therefore appears mainly to be due to temperature dependent alterations in the membrane skeleton topology.