In vitro effect of temperature on the conformational structure and collagen binding of SdrF, a Staphylococcus epidermidis adhesin

Appl Microbiol Biotechnol. 2015 Jul;99(13):5593-603. doi: 10.1007/s00253-015-6456-x. Epub 2015 Feb 17.

Abstract

Staphylococcus epidermidis is the leading etiologic agent of device-related infections. S. epidermidis is able to bind, by means of the adhesins of its cell wall, the host matrix proteins filming the artificial surfaces. Thence, bacteria cling to biomaterials and infection develops. The effect of temperature on integrity, structure, and biological activity of the collagen-binding adhesin (SdrF) of S. epidermidis has been here investigated. By cloning in E. coli XL1-Blue, a recombinant of the SdrF binding domain B (rSdrFB), carrying an N-terminal polyhistidine, was obtained. Purification was by HiTrap(TM) Chelating HP columns. Assessment of purity, molecular weight, and integrity was by SDS-PAGE. The rSdrFB-collagen binding was investigated by ELISA. A full three-dimensional reconstruction of rSdrFB was achieved by small-angle X-ray scattering (SAXS). At 25 °C, rSdrFB bound to type I collagen in a dose-dependent, saturable manner, with a Kd of 2.48 × 10(-7) M. When temperature increased from 25 to 37 °C, a strong conformational change occurred, together with the abolition of the rSdrFB-collagen binding. The rSdrFB integrity was not affected by temperature variation. SdrFB-collagen binding is switched on/off depending on the temperature. Implications with the infection pathogenesis are enlightened.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / chemistry*
  • Adhesins, Bacterial / genetics
  • Adhesins, Bacterial / isolation & purification
  • Adhesins, Bacterial / metabolism*
  • Collagen / metabolism*
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme-Linked Immunosorbent Assay
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Models, Molecular
  • Molecular Weight
  • Protein Binding / radiation effects
  • Protein Conformation / radiation effects*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Scattering, Small Angle
  • Staphylococcus epidermidis / chemistry*
  • Staphylococcus epidermidis / genetics
  • Temperature

Substances

  • Adhesins, Bacterial
  • Recombinant Proteins
  • Collagen