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Structure, Flexibility and Intramolecular Forces Observed on Individual Proteins Using Afm

Published online by Cambridge University Press:  02 July 2020

Daniel J. Müller  and
Andreas Engel
Daniel J. Müller
Affiliation:
M. E. Müller-lnstitut, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.
Andreas Engel
Affiliation:
M. E. Müller-lnstitut, Biozentrum, University of Basel, CH-4056 Basel, Switzerland.
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Extract

Atomic force microscopy (AFM) allows the surfaces of native biological macromolecules to be imaged in aqueous solution with submolecular resolution. Short range forces govern the interactions between the AFM tip and the sample and produce the submolecular information of high resolution topographs. In contrast, the long range electrostatic double-layer (EDL) force can be adjusted by pH and electrolytes to distribute the force applied to the AFM tip over a large sample area [1]. As demonstrated on fragile biological samples, adjustment of the electrolyte solution results in a local reduction of both vertical and lateral forces between the AFM tip and proteineous substructures. Consequently, the deformation of the native protein is minimized and polypeptide loops of individual proteins were imaged in aqueous solution with a lateral resolution < 5 Åand a vertical resolution < 1 Å (Fig. 1).

Type
Biological Applications of Scanning Probe Microscopies
Information
Microscopy and Microanalysis , Volume 5 , Issue S2: Proceedings: Microscopy & Microanalysis '99, Microscopy Society of America 57th Annual Meeting, Microbeam Analysis Society 33rd Annual Meeting, Portland, Oregon August 1-5, 1999 , August 1999 , pp. 996 - 997
Copyright
Copyright © Microscopy Society of America

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References

1Müller, D.J., Fotiadis, D., Scheuring, S., Müller, S.A. and Engel, A. (1999). Adjustment of electrolyte concentration promotes reproducible subnanometer imaging of biological specimens by atomic force microscopy. Biophys. J. 76,1101–1111.CrossRefGoogle Scholar
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