title: Expression, purification and biochemical characterization of Schizosaccharomyces pombe Mcm4, 6 and 7.
abstract: BACKGROUND
  The hetero-hexamer of the eukaryotic minichromosome maintenance (MCM) proteins plays an essential role in replication of genomic DNA. The ring-shaped Mcm2-7 hexamers comprising one of each subunit show helicase activity in vitro, and form double-hexamers on DNA. The Mcm4/6/7 also forms a hexameric complex with helicase activity in vitro.
  
  
  RESULTS
  We used an Escherichiai coli expression system to express various domains of Schizosaccharomyces pombe Mcm4, 6 and 7 in order to characterize their domain structure, oligomeric states, and possible inter-/intra-subunit interactions. We also successfully employed a co-expression system to express Mcm4/6/7 at the same time in Escherichiai coli, and have purified functional Mcm4/6/7 complex in a hexameric state in high yield and purity, providing a means for generating large quantity of proteins for future structural and biochemical studies.
  
  
  CONCLUSIONS
  Based on our results and those of others, models were proposed for the subunit arrangement and architecture of both the Mcm4/6/7 hexamer and the Mcm2-7 double-hexamer.
authors: Graduate Program in Genetics, Molecular and Cell Biology, University of Southern California, Los Angeles, CA 90089, USA.
authors: Meng
authors: M
authors: Xu
authors: Y Paul
authors: YP
authors: Chang
authors: Xiaojiang S
authors: XS
authors: Chen
mesh_terms: D018797:Cell Cycle Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; D011485:Protein Binding; D055503:Protein Multimerization; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D012568:Schizosaccharomyces / Q000235:genetics* / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D029702:Schizosaccharomyces pombe Proteins; C514502:Mcm7 protein, S pombe; D064148:Minichromosome Maintenance Complex Component 4; D064151:Minichromosome Maintenance Complex Component 6; D064168:Minichromosome Maintenance Complex Component 7; C078490:mcm4 protein, S pombe; C092300:mcm6 protein, S pombe