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Biotin induces tetramerization of a recombinant monomeric avidin. A model for protein-protein interactions.

Authors
  • Laitinen, O H
  • Marttila, A T
  • Airenne, K J
  • Kulik, T
  • Livnah, O
  • Bayer, E A
  • Wilchek, M
  • Kulomaa, M S
Type
Published Article
Journal
Journal of Biological Chemistry
Publisher
American Society for Biochemistry & Molecular Biology (ASBMB)
Publication Date
Mar 16, 2001
Volume
276
Issue
11
Pages
8219–8224
Identifiers
PMID: 11076945
Source
Medline
License
Unknown

Abstract

Chicken avidin, a homotetramer that binds four molecules of biotin was converted to a monomeric form by successive mutations of interface residues to alanine. The major contribution to monomer formation was the mutation of two aspartic acid residues, which together account for ten hydrogen bonding interactions at the 1-4 interface. Mutation of these residues, together with the three hydrophobic residues at the 1-3 interface, led to stable monomer formation in the absence of biotin. Upon addition of biotin, the monomeric avidin reassociated to the tetramer, which exhibited properties similar to those of native avidin, with respect to biotin binding, thermostability, and protease resistance. To our knowledge, these unexpected results represent the first example of a small monovalent ligand that induces oligomerization of a monomeric protein. This study may suggest a biological role for low molecular weight ligands in inducing oligomerization and in maintaining the stability of multimeric protein assemblies.

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