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A New Approach for the Comparative Analysis of Multiprotein Complexes Based on 15N Metabolic Labeling and Quantitative Mass Spectrometry
Published on: March 13, 2014
Structural studies of the archaeal MCM complex in different functional states
Alessandro Costa1, Tillmann Pape, Marin van Heel
1Division of Cell and Molecular Biology, Imperial College London SW7 2AZ, UK.
Journal of Structural Biology
|May 30, 2006
Summary
The Methanothermobacter thermoautotrophicus MCM complex changes its ring structure based on DNA and nucleotide binding. It forms double heptamers with nucleotide analogues and double hexamers with DNA, impacting helicase activity.
Area of Science:
- Structural biology
- Biochemistry
- Molecular biology
Background:
- The MCM2-7 complex is the main eukaryotic replicative helicase.
- Archaeal MCM complexes serve as simpler models for structure-function studies.
- Previous studies revealed MCM complexes can form single or double rings with varying subunit numbers.
Purpose of the Study:
- To investigate the stoichiometry changes in the Methanothermobacter thermoautotrophicus MCM complex.
- To understand how nucleotide analogues and DNA binding affect MCM complex structure.
- To correlate structural changes with helicase function.
Main Methods:
- Single-particle electron microscopy
- Multivariate statistical symmetry analysis
- Crystallography of the N-terminal domain
Main Results:
- MCM complex forms double-ring structures upon nucleotide or DNA binding.
- Nucleotide analogue binding favors double heptamer formation.
- Double-stranded DNA binding leads to a double hexamer structure.
Conclusions:
- MCM complex stoichiometry is dynamic and responsive to its environment.
- Different stoichiometries may play roles in regulating helicase activity.
- This study provides insights into the mechanism of helicase function.
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