By default, the server predicts bonding state of all CYS and HIS, as well as metal binding geometry. Prediction accuracy can be improved by entering additional information if available. If you know that the chain belongs to a metalloprotein (e.g. because of a high-throughput X-ray absorption spectroscopy experiment) click the checkbox below (note: in this case CYS are predicted in two classes: metal-bound/non metal-bound). In addition, if have a reasonable guess of the bonding state of CYS and HIS, click the second checkbox to input positions that are known to be metal-bound. You can either write a comma-separated list of ligand positions in the textarea below, or click on C and H symbols in the sequence copied below. Note: if you press a key in the above sequence textarea, the list is cleared.