Core mutations switch monomeric protein GB1 into an intertwined tetramer


The structure of a mutant immunoglobulin-binding B1 domain of streptococcal protein G (GB1), which comprises five conservative changes in hydrophobic core residues, was determined by NMR spectroscopy and X-ray crystallography. The oligomeric state and quaternary structure of the mutant protein are drastically changed from the wild type protein. The mutant structure consists of a symmetric tetramer, with intermolecular strand exchange involving all four units. Four of the five secondary structure elements present in the monomeric wild type GB1 structure are retained in the tetrameric structure, although their intra- and intermolecular interactions are altered. Our results demonstrate that through the acquisition of a moderate number of pivotal point mutations, proteins such as GB1 are able to undergo drastic structural changes, overcoming reduced stability of the monomeric unit by multimerization. The present structure is an illustrative example of how proteins exploit the breadth of conformational space.

Submission Details

ID: Qjb7qS2o3

Submitter: Admin Admin

Submission Date: July 31, 2017, 11:46 a.m.

Version: 3

Publication Details
Frank MK;Dyda F;Dobrodumov A;Gronenborn AM,Nat Struct Biol (2002) Core mutations switch monomeric protein GB1 into an intertwined tetramer. PMID:12379842
Additional Information

Study Summary

Number of data points 2
Proteins Protein Gβ1
Unique complexes 1
Assays/Quantities/Protocols Experimental Assay: Cm ; Experimental Assay: Tm
Libraries Tm and Cm of a 5-fold core mutant with tetrameric structure

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)