[1] Newcastle Univ, Inst Cell & Mol Biosci, Newcastle upon Tyne NE2 4HH, Tyne & Wear, England
[2] Lund Univ, Dept Biochem, Ctr Chem & Chem Engn, S-22100 Lund, Sweden
[3] Royal Inst Technol KTH, Sch Biotechnol, AlbaNova Univ Ctr, S-10691 Stockholm, Sweden