Identification of amino acids important for the biochemical activity of Methanothermobacter thermautotrophicus MCM.

Methanothermobacter thermautotrophicus minichromosomal maintenance protein (mtMCM) is a 75 kDa protein that self-assembles into a double hexamer structure. The double hexamer formed by the N-terminal region of mtMCM has a highly charged (overwhelmingly net positive) inner channel. Here we investigate the effects of point mutations of some of these charged residues on the biological activities of mtMCM.

Biochemical activities of the BOB1 mutant in Methanobacterium thermoautotrophicum MCM.

Minichromosomal maintenance proteins (MCMs) are considered to be the replicative helicase. Methanobacterium thermoautotrophicum has a single MCM gene (mtMCM). The crystal structure of the mtMCM N-terminal region is a double hexamer.

Polymorphism and double hexamer structure in the archaeal minichromosome maintenance (MCM) helicase from Methanobacterium thermoautotrophicum.

Methanobacterium thermoautotrophicum minichromosome maintenance complex (mtMCM), a cellular replicative helicase, is a useful model for the more complex eukaryotic MCMs. Biochemical and crystallographic evidence indicates that mtMCM assembles as a double hexamer (dHex), but previous electron microscopy studies reported only the presence of single heptamers or single hexamers (Pape, T., Meka, H.

Double hexamer disruption and biochemical activities of Methanobacterium thermoautotrophicum MCM.

Methanobacterium thermoautotrophicum MCM (mtMCM) is a helicase required for DNA replication. Previous electron microscopy studies have shown mtMCM in several oligomeric forms. However, biochemical studies suggest that mtMCM is a dodecamer, likely a double hexamer (dHex).

Two heads are better than one: regulation of DNA replication by hexameric helicases.

DNA replication is tightly regulated in a cell cycle to ensure the integrity of genomic information during successive passages. The replication process can be divided into three major steps as follows: the initial assembly of prereplication complex (pre-RC) at the replication origin, the distortion of the origin (or origin melting) for replication initiation, and the elongation phase during DNA synthesis. In this process, long stretches of double-stranded DNA (dsDNA) must be unzipped in a relatively short time window within a cell growth cycle.

The structure and function of MCM from archaeal M. Thermoautotrophicum.

Eukaryotic chromosomal DNA is licensed for replication precisely once in each cell cycle. The mini-chromosome maintenance (MCM) complex plays a role in this replication licensing. We have determined the structure of a fragment of MCM from Methanobacterium thermoautotrophicum (mtMCM), a model system for eukaryotic MCM.