Abstract
Structural maintenance of chromosomes (SMC) proteins form a V-shaped dimer in which a central hinge domain connects two coiled-coil arms, each having an ATP binding head domain at its distal end. Here, we show that the hinge domain plays essential roles in modulating the mechanochemical cycle of SMC proteins. An initial interaction of the hinge domain with DNA leads to opening of the arms by triggering hydrolysis of ATP bound to the head domains, which are located approximately 50 nm away from the hinge. This conformational change allows the inner surface of the hinge domain to stably interact with DNA by an ATP-independent mechanism and primes ATP-driven engagement between the liberated head domains either intramolecularly or intermolecularly. Consistently, a variety of hinge mutations drastically alter DNA binding properties of SMC proteins through distinct mechanisms. Our results suggest that SMC proteins possess an intrinsic property to change their own conformations upon binding to DNA.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
MeSH terms
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Adenosine Triphosphatases / chemistry*
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphatases / metabolism*
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Adenosine Triphosphate / metabolism
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Amino Acid Sequence
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Archaeal Proteins / chemistry
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Archaeal Proteins / genetics
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Archaeal Proteins / metabolism
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Bacterial Proteins / chemistry
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism
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Binding Sites / genetics
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Chromosomal Proteins, Non-Histone / chemistry*
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Chromosomal Proteins, Non-Histone / genetics
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Chromosomal Proteins, Non-Histone / metabolism*
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DNA / metabolism*
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Enzyme Activation
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Humans
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In Vitro Techniques
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Kinetics
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Models, Biological
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Models, Molecular
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Molecular Sequence Data
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Point Mutation
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Protein Structure, Tertiary
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Sequence Homology, Amino Acid
Substances
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Archaeal Proteins
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Bacterial Proteins
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Chromosomal Proteins, Non-Histone
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Recombinant Proteins
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Adenosine Triphosphate
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DNA
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Adenosine Triphosphatases