Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.|Biomolecular Structure Research Center and Department of Molecular Biology, Università di Siena, I-53100 Siena, Italy.