PROSITE documentation PDOC00662

MCM family signature and profile

Proteins shown to be required for the initiation of eukaryotic DNA replication share a highly conserved domain of about 210 amino-acid residues [1,2,3]. The latter shows some similarities [4] with that of various other families of DNA-dependent ATPases. Eukaryotes seem to possess a family of six proteins that contain this domain. They were first identified in yeast where most of them have a direct role in the initiation of chromosomal DNA replication by interacting directly with autonomously replicating sequences (ARS). They were thus called 'minichromosome maintenance proteins' with gene symbols prefixed by MCM. These six proteins are:

• MCM2, also known as cdc19 (in S.pombe) [E1].
• MCM3, also known as DNA polymerase α holoenzyme-associated protein P1, RLF β subunit or ROA.
• MCM4, also known as CDC54, cdc21 (in S.pombe) or dpa (in Drosophila).
• MCM5, also known as CDC46 or nda4 (in S.pombe).
• MCM6, also known as mis5 (in S.pombe).
• MCM7, also known as CDC47 or Prolifera (in A.thaliana).

This family is also present in archebacteria. In Methanococcus jannaschii there are four members: MJ0363, MJ0961, MJ1489 and MJECL13.

The presence of a putative ATP-binding domain implies that these proteins may be involved in an ATP-consuming step in the initiation of DNA replication in eukaryotes.

As a signature pattern, we selected a perfectly conserved region that represents a special version of the B motif found in ATP-binding proteins.