Global metal-ion Binding protein Fingerprint: a Method to Identify Motif-Less metal-ion Binding proteins

Metal-ion binding proteins play a vital role in biological processes. Identifying putative metal-ion binding proteins is through knowledge-based methods. These involve the identification of specific motifs that characterize a specific class of metal-ion binding protein. Metal-ion binding motifs have been identified for the common metal ions. A robust global fingerprint that is useful in identifying a metal-ion binding protein from a non-metal-ion binding protein has not been devised. Such a method will help in identifying novel metal-ion binding proteins and proteins that do not possess a canonical metal-ion binding motif. We have used a set of physico-chemical parameters of metal-ion binding proteins encoded by the genes CzcA, CzcB and CzcD as a training set to supervised classifiers and have been able to identify several other metal ion binding proteins leading us to believe that metal-ion binding proteins have a global fingerprint, which cannot be pinned down to a single feature of the protein sequence.