5.5.1.B6 | AknH forms a tetramer of 222 symmetry. Two subunits (A-B and C-D, respectively), related by one of the 2-fold symmetry axes, form tight dimer interfaces. The side-chains of Thr128, Gln105 and the main-chain nitrogen of Val92 each interact with oxygen atoms of the polyketide core of the product via a water molecule. Additional enzyme-ligand interactions involve residues Arg120 and Trp122 from the other monomer across the subunit-subunit interface |