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Recombinant Protein Expression, Crystallization, and Biophysical Studies of a Bacillus-conserved Nucleotide Pyrophosphorylase, BcMazG
Published on: May 16, 2017
A biochemically active MCM-like helicase in Bacillus cereus.
Martin Samuels1, Gaurav Gulati, Jae-Ho Shin
1Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Nucleic Acids Research
|May 29, 2009
Summary
A novel mini-chromosome maintenance (MCM) protein from Bacillus cereus (BcMCM) exhibits helicase and ATPase activity. This divergent MCM protein provides a unique model for studying essential replicative helicases.
Area of Science:
- Molecular Biology
- Biochemistry
- Microbiology
Background:
- Mini-chromosome maintenance (MCM) proteins are essential replicative helicases in archaea and eukaryotes.
- A unique MCM homolog (BcMCM) was identified in a phage integrated within Bacillus cereus.
Purpose of the Study:
- To characterize the enzymatic activities and structural features of BcMCM.
- To investigate the functional implications of its divergent amino-terminus.
- To establish BcMCM as a model for understanding MCM helicase function.
Main Methods:
- BLAST analysis for identifying MCM homolog.
- Biochemical assays to determine helicase and ATPase activity.
- Analysis of ssDNA binding and zinc atom presence in the amino-terminus.
Main Results:
- BcMCM demonstrates 3'-->5' helicase and single-stranded DNA (ssDNA)-stimulated ATPase activity, originating from its AAA domain.
- BcMCM functions as a monomer in solution but likely oligomerizes in vivo.
- The divergent amino-terminus binds ssDNA and contains a zinc atom, similar to typical MCM proteins, but lacks primase activity.
Conclusions:
- BcMCM represents a divergent MCM paralog with a unique amino-terminus.
- Despite structural differences, BcMCM performs essential MCM helicase functions.
- BcMCM serves as a valuable model for studying the conserved functions of MCM replicative helicases.
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