Sandbox Reserved 307: Difference between revisions

EF-Tu is a 12 chain structure in E. coli that tends to form a complex with the antibiotic tetracycline. Two different crystalline forms of the structure have been identified <ref name="gp"/>. In the first crystal form, P21, six copies of EF-Tu, GDP, tetracycline, and Mg2+ are arranged as dimers in an asymmetric manner <ref name="gp"/>. An alternative form, P43212, is a monomeric, asymmetric unit with tetracycline complexes within the structure <ref name="gp"/>.  

The P21 structure forms a final complex consisting of six EF-Tu proteins, GDP, tetracycline, Mg2+, and 244 water molecules<ref name="gp"/>. The final complex of the P43212 crystal is composed of one protein copy, GDP, tetracycline, Mg2+, SO2, glyoxylic acid, 3 Na+ and 160 H2O molecules <ref name="gp"/>.  In either case, the binding site for tetracycline is located in domain one, allowing it to interact with the major functional groups. Residues Tet O11 and Tet O12 of tetracycline co-ordinate Mg2+ <ref name="gp"/>. There is also an interaction with the phosphate of the GDP and the residues Thr25 and Asp80 <ref name="gp"/>. When bound, tetracycline replaces two well ordered water molecules from the EF-Tu structure.