Expression, crystallization and preliminary X-ray analysis of an outer membrane protein from Thermus thermophilus HB27

The predicted eight-stranded β-barrel outer membrane protein TTC0834 from T. thermophilus HB27 was overexpressed in T. thermophilus HB8 and crystallized. Diffraction data were collected to a maximal resolution of 3.2 Å. The cell envelope of the thermophilic bacterium Thermus thermophilus is multilayered and includes an outer membrane with integral outer membrane proteins that are not well characterized. The hypothetical protein TTC0834 from T. thermophilus HB27 was identified as a 22 kDa outer membrane protein containing eight predicted β-strands. TTC0834 was expressed with an N-terminal His tag in T. thermophilus HB8 and detected in the S-layer/outer membrane envelope fraction. His-TTC0834 was purified and crystallized under various conditions. Native data sets were collected to 3.2 Å resolution and the best diffracting crystals belonged to space group P3₁21 or P3₂21, with unit-cell parameters a = b = 166.67, c = 97.53 Å