1. Centre for Proteome Research, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.
2. Faculty of Medical Sciences, Biosciences Institute, Newcastle University, Newcastle Upon Tyne NE2 4HH, U.K.
3. Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Liverpool L69 7ZB, U.K.