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Cryoelectron Microscopy of Red Cell Skeletons Reveals that Spectrin has a Helical Conformation

Published online by Cambridge University Press:  02 July 2020

Li Yang
Affiliation:
Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL60637
Robert Josephs
Affiliation:
Department of Molecular Genetics and Cell Biology, The University of Chicago, Chicago, IL60637
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Extract

In vivo the red blood cell reversibly and rapidly deforms as it passes through the small capillaries. Although the physiochemical basis of the red cell's deformability is unknown, it is regarded as being a property of the membrane protein spectrin. We have used cryoelectron microscopy to study the structure of spectrin in membrane skeletons to determine how its molecular structure confers elastic properties on the cell membrane. Cryomicroscopy has the virtue of minimally perturbing easily deformable structures such as spectrin.

Figure 1 is an electron micrograph of a portion of a frozen-hydrated red cell skeleton. The spectrin molecules are indicated by the arrow heads. They cross link the skeletal network by interacting with short rod like segments F-actin (indicated by the arrows) containing about 13 actin molecules. In such micrographs the spectrin appears to have a sinusoidal shape whereas in negatively stained preparations spectrin appears to be straight.

We have used the procedure of Margalef in order to determine the three dimensional trajectory of the spectrin molecule.

Type
From Scanning Probe Microscopy to High Resolution Ultrasound: New Versions of the Vasculature
Copyright
Copyright © Microscopy Society of America 1997

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References

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5. This work was supported by NIH grant HL22654. We wish to thank Dr.Francesc, P. I Margalef for providing the Flying Cylinder software and instructions for its usage.Google Scholar