title: Arabidopsis thaliana MCM3 single subunit of MCM2-7 complex functions as 3' to 5' DNA helicase.
abstract: Minichromosome maintenance 2-7 (MCM2-7) proteins are conserved eukaryotic replicative factors essential for the DNA replication at its initiation and elongation step, and act as a licensing factor. The MCM2-7 and MCM4/6/7subcomplex exhibit DNA helicase activity, and are therefore regarded as the replicative helicase. The MCM proteins have not been studied in detail in plant system. Here, we present the biochemical characterization of Arabidopsis thaliana MCM3 single subunit and show that it exhibits in vitro unwinding and ATPase activities. AtMCM3 shows a greater unwinding activity with 5' forked partial DNA duplex substrate as compared to 3' forked and non-forked substrates. ATP and magnesium ion are indispensable for its DNA helicase activity. Specifically, ATP and dATP are the preferred nucleotides for its unwinding activity. The directionality of the AtMCM3 has been determined to be in 3' to 5' direction. The oligomerization status of AtMCM3 single subunit protein indicates that it is present in different multimeric forms. The unraveling of the helicase activity of AtMCM3 will provide better insights into the plant DNA replication.
authors.affiliation: Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Irum
authors.initials: I
authors.lastname: Rizvi
authors.affiliation: Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India.
authors.forename: Nirupam Roy
authors.initials: NR
authors.lastname: Choudhury
authors.affiliation: Plant Molecular Biology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi, 110067, India. narendra@icgeb.res.in.
authors.forename: Narendra
authors.initials: N
authors.lastname: Tuteja
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000502:physiology; D055162:Biocatalysis; D018744:DNA, Plant / Q000737:chemistry; D004277:DNA, Single-Stranded / Q000737:chemistry; D006868:Hydrolysis; D064126:Minichromosome Maintenance Complex Component 3 / Q000737:chemistry* / Q000502:physiology; D011485:Protein Binding; D020836:Protein Structure, Quaternary
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D004277:DNA, Single-Stranded; D000255:Adenosine Triphosphate; C000612706:MCM3 protein, Arabidopsis; D064126:Minichromosome Maintenance Complex Component 3
keywords: ATPase; Arabidopsis thaliana; DNA helicase; MCM3; Native PAGE