[‡
]Max Delbrueck Center for Molecular
Medicine, D-13125 Berlin, the
[§
]Department of
Biology/Biophysics, Humboldt University Berlin, D-10115 Berlin, the
[¶
]Department of Molecular Biology, Max Planck
Institute for Infection Biology, D-10117 Berlin, and the
[∥
]Department of Biology, Technische
Universität Darmstadt, D-64287 Darmstadt, Germany