Exploring local and non-local interactions for protein stability by structural motif engineering.


Abstract

In order to probe the relative contribution of local and non-local interactions to the thermodynamic stability of proteins, we have devised an experimental approach based on a combination of motif engineering and sequence shuffling. Candidate chain segments in an immunoglobulin V(L) domain were identified whose conformation is proposed to be dominated by non-local interactions. Locally interacting structural motifs of a different conformation were then constructed as replacements, by introducing motif consensus sequences. We find that all nine replacements we constructed systematically reduce the folding cooperativity. By comparing this destabilising effect with the folding transitions of shuffled sequences for three of these motifs, we estimate the contribution of local, native interactions to the free energy of folding. Our results suggest that local and non-local interactions contribute to stability by an approximately equal amount, but that local interactions stabilise by increasing the resistance to denaturation while non-local interactions increase folding cooperativity. The systematic loss of stability by sequence shuffling in these host-guest experiments suggests that the designed interactions indeed are present in the native state, thus consensus sequence engineering may be a useful tool in structure design, but non-local interactions must be taken into account for global stability engineering. Statistical approaches are powerful tools for engineering protein structure and stability, but an analysis based on local sequence propensities alone does not adequately represent the balance of sequence and context in protein structures. Study holds ProTherm entries: 8269, 8270, 8271, 8272, 8273, 8274, 8275, 8276, 8277, 8278 Extra Details: protein engineering; protein stability; protein folding; structural motifs;,immunoglobulin variable domains

Submission Details

ID: 7Zb5oGmx

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:35 p.m.

Version: 1

Publication Details
Niggemann M;Steipe B,J. Mol. Biol. (2000) Exploring local and non-local interactions for protein stability by structural motif engineering. PMID:10656826
Additional Information

Sequence Assay Result Units