Three-dimensional structures of avidin and the avidin-biotin complex

Oded Livnah*, Edward A. Bayer, Meir Wilchek, Joel L. Sussman

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

592 Scopus citations

Abstract

The crystal structures of a deglycosylated form of the egg-white glycoprotein avidin and of its complex with biotin have been determined to 2.6 and 3.0 A, respectively. The structures reveal the amino acid residues critical for stabilization of the tetrameric assembly and for the exceptionally tight binding of biotin. Each monomer is an eight-stranded antiparallel β-barrel, remarkably similar to that of the genetically distinct bacterial analog streptavidin. As in streptavidin, binding of biotin involves a highly stabilized network of polar and hydrophobic interactions. There are, however, some differences. The presence of additional hydrophobic and hydrophilic groups in the binding site of avidin (which are missing in streptavidin) may account for its higher affinity constant. Two amino acid substitutions are proposed to be responsible for its susceptibility to denaturation relative to streptavidin. Unexpectedly, a residual N-acetylglucosamine moiety was detected in the deglycosylated avidin monomer by difference Fourier synthesis.

Original languageAmerican English
Pages (from-to)5076-5080
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume90
Issue number11
StatePublished - 1 Jun 1993
Externally publishedYes

Keywords

  • Deglycosylated avidin
  • Divergent evolution
  • Streptavidin
  • X-ray crystallography

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