Trace element utilisation project.

I have recently been set the task of carrying out a research project based on trace element utilisation. After countless hours reading into trace elements and how different species from the three kingdoms of life utilise these (transporter/user proteins), I've now been told that I have to start producing some data using blastp. I will be using dbTEU, which has roughly 16,500 protein sequences for trace element-containing proteins, from ~700 species from the three kingdoms of life. However, I'm unsure as to what what to "investigate". I'm thinking of using blastp to compare similarities and differences in protein sequences between species, would this be a viable project? For example, comparing protein sequences from species in the same kingdom and then between species from different kingdoms etc. Working towards a hypothesis along the lines of, if all organisms evolved from a common ancestor, then there will be common/similar properties of trace element utilisation in species from all three kingdoms of life.

Help/advice/pointers very much appreciated.