Abstract
Natural selection shapes protein solubility to physiological requirements and recombinant applications that require higher protein concentrations are often problematic. This raises the question whether the solubility of natural protein sequences can be improved. We here show an anti-correlation between the number of aggregation prone regions (APRs) in a protein sequence and its solubility, suggesting that mutational suppression of APRs provides a simple strategy to increase protein solubility. We show that mutations at specific positions within a protein structure can act as APR suppressors without affecting protein stability. These hot spots for protein solubility are both structure and sequence dependent but can be computationally predicted. We demonstrate this by reducing the aggregation of human α-galactosidase and protective antigen of Bacillus anthracis through mutation. Our results indicate that many proteins possess hot spots allowing to adapt protein solubility independently of structure and function.
Highlights
Natural selection shapes protein solubility to physiological requirements and recombinant applications that require higher protein concentrations are often problematic
Hydrophobicity is often an important driver for phase separation of misfolded proteins, structural aggregation itself is geared by more specific interactions between identical linear aggregation prone sequence regions (APRs) within the primary sequence that assemble by intermolecular b-strand interactions
We used the predicted change in aggregation propensity (TANGO) to predict all aggregation prone regions (APRs) in the E. coli proteome and matched these (1) to E. coli protein solubility (3,173 proteins) as measured by Niwa et al.[17] using in vitro translation and (2) to cellular abundance (597 proteins) data obtained by Vogel et al.[18] using mass spectrometry (Supplementary Fig. 1A)
Summary
Natural selection shapes protein solubility to physiological requirements and recombinant applications that require higher protein concentrations are often problematic. On average a globular protein domain contains 2–4 APRs and B20% of the total protein sequence of any given proteome is part of APRs13,14 It was demonstrated on a large set of Escherichia coli proteins that the intrinsic aggregation propensity of folded proteins correlates with their solubility[15]. Our structural analysis demonstrates this selective pressure is not saturated but dictated by physiological requirements in protein abundance and as a result most proteins have potential for increased solubility We illustrate these principles with two examples in which we introduced mutations in these structural hotspots thereby increasing resistance to protein aggregation without affecting structure or function: a-galactosidase, a protein currently used in replacement therapy for Fabry’s disease and the anthrax protective antigen, a key component for recombinant anthrax vaccines
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
