科研之友
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摘要
Extremophiles, microorganisms thriving in extreme environmental conditions, must have proteins and nucleic acids that are stable at extremes of temperature and pH. The nonenveloped, rod-shaped virus SIRV2 (Sulfolobus islandicus rod-shaped virus 2) infects the hyperthermophilic acidophile Sulfolobus islandicus, which lives at 80 degrees C and pH 3. We have used cryo-electron microscopy to generate a three-dimensional reconstruction of the SIRV2 virion at similar to 4 angstrom resolution, which revealed a previously unknown form of virion organization. Although almost half of the capsid protein is unstructured in solution, this unstructured region folds in the virion into a single extended a helix that wraps around the DNA. The DNA is entirely in the A-form, which suggests a common mechanism with bacterial spores for protecting DNA in the most adverse environments.
- 出版日期2015-5-22
