Structure of a fatty-acid-binding protein from Bacillus subtilis determined by sulfur-SAD phasing using in-house chromium radiation

Acta Crystallogr D Biol Crystallogr. 2009 May;65(Pt 5):440-8. doi: 10.1107/S0907444909007756. Epub 2009 Apr 18.

Abstract

Sulfur single-wavelength anomalous dispersion (S-SAD) and halide-soaking methods are increasingly being used for ab initio phasing. With the introduction of in-house Cr X-ray sources, these methods benefit from the enhanced anomalous scattering of S and halide atoms, respectively. Here, these methods were combined to determine the crystal structure of BsDegV, a DegV protein-family member from Bacillus subtilis. The protein was cocrystallized with bromide and low-redundancy data were collected to 2.5 A resolution using Cr Kalpha radiation. 17 heavy-atom sites (ten sulfurs and seven bromides) were located using standard methods. The anomalous scattering of some of the BsDegV S atoms and Br atoms was weak, thus neither sulfurs nor bromides could be used alone for structure determination using the collected data. When all 17 heavy-atom sites were used for SAD phasing, an easily interpretable electron-density map was obtained after density modification. The model of BsDegV was built automatically and a palmitate was found tightly bound in the active site. Sequence alignment and comparisons with other known DegV structures provided further insight into the specificity of fatty-acid selection and recognition within this protein family.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacillus subtilis / chemistry*
  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism
  • Binding Sites
  • Bromides
  • Chromium
  • Crystallography, X-Ray / methods*
  • Models, Molecular
  • Molecular Sequence Data
  • Palmitates / metabolism
  • Protein Conformation
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / isolation & purification
  • Recombinant Fusion Proteins / metabolism
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Sulfur

Substances

  • Bacterial Proteins
  • Bromides
  • Palmitates
  • Recombinant Fusion Proteins
  • Chromium
  • Sulfur