Engineering a thermostable protein via optimization of charge-charge interactions on the protein surface.


Abstract

A simple theoretical model for increasing the protein stability by adequately redesigning the distribution of charged residues on the surface of the native protein was tested experimentally. Using the molecule of ubiquitin as a model system, we predicted possible amino acid substitutions on the surface of this protein which would lead to an increase in its stability. Experimental validation for this prediction was achieved by measuring the stabilities of single-site-substituted ubiquitin variants using urea-induced unfolding monitored by far-UV CD spectroscopy. We show that the generated variants of ubiquitin are indeed more stable than the wild-type protein, in qualitative agreement with the theoretical prediction. As a positive control, theoretical predictions for destabilizing amino acid substitutions on the surface of the ubiquitin molecule were considered as well. These predictions were also tested experimentally using correspondingly designed variants of ubiquitin. We found that these variants are less stable than the wild-type protein, again in agreement with the theoretical prediction. These observations provide guidelines for rational design of more stable proteins and suggest a possible mechanism of structural stability of proteins from thermophilic organisms.

Submission Details

ID: kTdWdqUH3

Submitter: Connie Wang

Submission Date: Aug. 8, 2017, 11:18 a.m.

Version: 1

Publication Details
Loladze VV;Ibarra-Molero B;Sanchez-Ruiz JM;Makhatadze GI,Biochemistry (1999) Engineering a thermostable protein via optimization of charge-charge interactions on the protein surface. PMID:10600102
Additional Information

Number of data points 30
Proteins Polyubiquitin-C
Unique complexes 10
Assays/Quantities/Protocols Experimental Assay: Cm ; Experimental Assay: ∆G(kJ/mol)
Libraries Structural and Thermodynamic Description of Ubiquitin Variants
Sequence Assay Result Units