Crystallization and preliminary X-ray diffraction analysis of the truncated cytosolic domain of the iron transporter FeoB

FeoB-family proteins are widely distributed in bacteria and archaea and are involved in high-affinity Fe²⁺ uptake through the plasma membrane. FeoB consists of an N-terminal cytosolic region followed by a C-terminal trans­membrane region. The cytosolic region contains small GTPase and GDP dissociation inhibitor-like domains, which serve a regulatory function. The truncated cytosolic region of the iron transporter FeoB from Thermotoga maritima was overexpressed, purified and crystallized. Four native or SeMet crystal forms in a nucleotide-free state or in complex with either GDP or GMPPNP diffracted to resolutions of between 1.5 and 2.1 Å.