Cavities Destabilize Proteins (IMAGE) Aarhus University Caption The well-characterized variant, L99A, of the protein lysozyme from phage T4 was used to identify invisible folded and partially unfolded states by Nuclear Magnetic Resonance (NMR) spectroscopy, among others. Credit Proc Natl Acad Sci U S A, copyright 2019 National Academy of Sciences. Usage Restrictions Image may be used only to illustrate the research described in the accompanying release. Credit required: Proc Natl Acad Sci U S A, copyright 2019 National Academy of Sciences. License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.