Institute of Biotechnology, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland.|Institute of Biotechnology, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland.|Institute of Biotechnology, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland.|Institute of Biotechnology, P.O. Box 56 (Viikinkaari 5), FI-00014 University of Helsinki, Finland.