1mpe
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Ensemble of 20 structures of the tetrameric mutant of the B1 domain of streptococcal protein G
OverviewOverview
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.
About this StructureAbout this Structure
1MPE is a Single protein structure of sequence from Streptococcus sp. group g. Full crystallographic information is available from OCA.
ReferenceReference
Core mutations switch monomeric protein GB1 into an intertwined tetramer., Kirsten Frank M, Dyda F, Dobrodumov A, Gronenborn AM, Nat Struct Biol. 2002 Nov;9(11):877-85. PMID:12379842
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