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Conformational stability of dimeric proteins: Quantitative studies by equilibrium denaturation
Author(s) -
Neet Kenneth E.,
Timm David E.
Publication year - 1994
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560031202
Subject(s) - dimer , chemistry , denaturation (fissile materials) , guanidine , equilibrium unfolding , monomer , protein folding , crystallography , globular protein , dissociation (chemistry) , protein subunit , protein quaternary structure , sedimentation equilibrium , protein structure , chemical stability , circular dichroism , biochemistry , organic chemistry , ultracentrifuge , gene , nuclear chemistry , polymer
The conformational stability of dimeric globular proteins can be measured by equilibrium denaturation studies in solvents such as guanidine hydrochloride or urea. Many dimeric proteins denature with a 2‐state equilibrium transition, whereas others have stable intermediates in the process. For those proteins showing a single transition of native dimer to denatured monomer, the conformational stabilities, δ G u (H 2 O), range from 10 to 27 kcal/mol, which is significantly greater than the conformational stability found for monomeric proteins. The relative contribution of quaternary interactions to the overall stability of the dimer can be estimated by comparing G u (H 2 O) from equilibrium denaturation studies to the free energy associated with simple dissociation in the absence of denaturant. In many cases the large stabilization energy of dimers is primarily due to the intersubunit interactions and thus gives a rationale for the formation of oligomers. The magnitude of the conformational stability is related to the size of the polypeptide in the subunit and depends upon the type of structure in the subunit interface. The practical use, interpretation, and utility of estimation of conformational stability of dimers by equilibrium denaturation methods are discussed.