Abstract
The cation diffusion facilitator (CDF) family proteins are ubiquitously distributed in the three domains of life and transport metals such as zinc and various heavy metals. Prokaryotic CDF proteins consists of an N-terminal putative six-transmembrane domain followed by a C-terminal cytosolic domain. The cytosolic domain of the CDF-family protein from Thermotoga maritima has been overexpressed, purified and crystallized. The selenomethionine-substituted crystals diffracted X-rays to 2.5 A resolution using synchrotron radiation, belonged to space group R32, with unit-cell parameters a = b = 97.7, c = 83.4 A, and are expected to contain one molecule in each asymmetric unit.