1. Plant Biochemistry Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK–1871 Frederiksberg C, Copenhagen, Denmark (S.E.T., H.V.S., B.L.M.);
2. Department of Biochemistry, Stockholm University, SE–10609 Stockholm, Sweden (S.E.T., B.A.); and
3. Division of Cell Biology, Linköping University, SE–58185 Linköping, Sweden (B.A.)