- Science Director Dr. John Spence named Royal Society Fellow
- BioXFEL Graduate Student Joey Olmos (Rice) Earns NSF Graduate Research Fellowship
- Mapping Conformational Landscape Through Crystallography
- NSF BioXFEL researchers create a better way to find out ‘when’
- Taking the initiative on single particle imaging
- Tuesday, 30 May 2017 11:21
Although protein design has been used to introduce new functions, designed variants generally only function as well as natural proteins after rounds of laboratory evolution. One possibility for this pattern is that designed mutants frequently sample nonfunctional conformations.
To test this idea, we exploited advances in multiconformer modeling of room-temperature X-ray data collection on redesigned ubiquitin variants selected for increasing binding affinity to the deubiquitinase USP7. Initial core mutations disrupt natural packing and lead to increased flexibility. Additional, experimentally selected mutations quenched conformational heterogeneity through new stabilizing interactions. Stabilizing interactions, such as cation-pi stacking and ordered waters, which are not included in standard protein design energy functions, can create specific interactions that have long-range effects on flexibility across the protein. Our results suggest that increasing flexibility may be a useful strategy to escape local minima during initial directed evolution and protein design steps when creating new functions.