Steric effects on multivalent ligand-receptor binding: Exclusion of ligand sites by bound cell surface receptors

William S. Hlavacek, Richard G. Posner, Alan S. Perelson

Research output: Contribution to journalArticle

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Abstract

Steric effects can influence the binding of a cell surface receptor to a multivalent ligand. To account for steric effects arising from the size of a receptor and from the spacing of binding sites on a ligand, we extend a standard mathematical model for ligand-receptor interactions by introducing a steric hindrance factor. This factor gives the fraction of unbound ligand sites that are accessible to receptors, and thus available for binding, as a function of ligand site occupancy. We derive expressions for the steric hindrance factor for various cases in which the receptor covers a compact region on the ligand surface and the ligand expresses sites that are distributed regularly or randomly in one or two dimensions. These expressions are relevant for ligands such as linear polymers, proteins, and viruses. We also present numerical algorithms that can be used to calculate steric hindrance factors for other cases. These theoretical results allow us to quantify the effects of steric hindrance on ligand-receptor kinetics and equilibria.

Original languageEnglish (US)
Pages (from-to)3031-3043
Number of pages13
JournalBiophysical Journal
Volume76
Issue number6
DOIs
StatePublished - Jun 1999

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ASJC Scopus subject areas

  • Biophysics

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