Ionic switch controls the DNA state in phage λ

摘要: We have recently found that DNA packaged in phage λ undergoes a disordering transition triggered by temperature, which results increased genome mobility. This solid-to-fluid like markedly increases the number of infectious particles facilitating infection. However, structural strongly depends on temperature and ionic conditions surrounding medium. Using titration microcalorimetry combined with solution X-ray scattering, we mapped both energetic changes associated encapsidated λ-DNA. Packaged needs to reach critical stress level order for occur. varied capsid changing length conditions. striking evidence intracapsid is 'switched on' at mimicking those vivo also physiologic infection 37°C. ion regulated on-off switch mobility turn affects viral replication. These suggest remarkable adaptation environment its host bacteria human gut. The metastable state provides new paradigm physical evolution viruses.