BBK32, a fibronectin binding MSCRAMM from Borrelia burgdorferi, contains a disordered region that undergoes a conformational change on ligand binding

Jung Hwa Kim, Jenny Singvall, Ulrich Schwarz-Linek, Barbara J B Johnson, Jennifer R Potts, Magnus Höök

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BBK32 is a fibronectin-binding lipoprotein on Borrelia burgdorferi, the causative agent of Lyme disease. Analysis using secondary structure prediction programs suggested that BBK32 is composed of two domains, an N-terminal segment lacking well defined secondary structure and a C-terminal segment composed largely of alpha-helices. Analysis of purified recombinant forms of the two domains by circular dichroism spectroscopy, gel permeation chromatography, and intrinsic viscosity determination were consistent with an N-terminal-extended, unstructured segment and a C-terminal globular domain in BBK32. Solid phase binding experiments suggest that the unstructured N-terminal domain binds fibronectin. Analysis of changes in circular dichroism spectra of the N-terminal segment of BBK32 upon binding of the N-terminal domain of fibronectin revealed an increase in beta-sheet content in the complex. Hence, BBK32, which belongs to a different family of proteins and shows no overall sequence similarity with the fibronectin binding MSCRAMMs (microbial surface components recognizing adhesive matrix molecules) of Gram-positive bacteria, binds fibronectin by a mechanism that is reminiscent of the "tandem beta-zipper" previously demonstrated for the fibronectin binding of streptococcal adhesins.
Original languageEnglish
Pages (from-to)41706-14
Number of pages9
JournalJournal of Biological Chemistry
Issue number40
Publication statusPublished - 2004


  • Adhesins, Bacterial
  • Amino Acid Motifs
  • Bacterial Proteins
  • Borrelia burgdorferi Group
  • Fibronectins
  • Ligands
  • Protein Binding
  • Protein Conformation
  • Protein Structure, Secondary

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