Quantitative assessment of the relative contributions of steric repulsion and chemical interactions to macromolecular crowding§

Authors

  • Allen P. Minton

    Corresponding author
    1. Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD
    • Section on Physical Biochemistry, Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, MD
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  • This work is dedicated to the memory of Professor Henryk Eisenberg, under whose guidance the author was first introduced to the field of physical biochemistry. The interest in obtaining a quantitative understanding of the behavior of biological macromolecules that he inspired in me endures to this day.

  • This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com

  • §

    This article is a U.S. Government work and, as such, is in the public domain in the United States of America.

Abstract

The term “macromolecular crowding” denotes the combined effects of high volume fractions of nominally unrelated macromolecules upon the equilibrium and transport properties of all macrosolutes, dilute as well as concentrated, in the crowded medium. We present a formal partitioning of the total crowding effect into contributions from steric exclusion (excluded volume) and weak, nonspecific attractive interactions between a concentrated “crowding agent” and reactant and product species present at trace concentration. A numerical example of the combined effect of both steric and chemical interactions between crowder and tracer upon the reversible dimerization of tracer is presented, based upon reasonable estimates of the magnitude of both repulsive and attractive interactions between tracer and crowder species. © 2012Wiley Periodicals, Inc. Biopolymers 99: 239–244, 2013.

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