I'm using Pfam HMMs to identify domains in my T. cruzi proteins with the HMMER program.
I kinda understand that a HMM is build by a family multiple sequence alignment, by calculating probabilities of states.
But how the hmmscan works to classify a new protein by families HMMs? Where can I read more about this? Academic references would be appreciated.
Have you tried Googling? The Durbin book should have a chapter on HMMs and HMM based classification is a relatively common topic. You could start with HMMER paper's reference section and work backwards until you get to an explanation of how and why it's done.