Pathway · 1 proteins
Chromosome preparation
Replication and DNA topology enzymes contribute to chromosome readiness.
How it works
- DnaA, DNA polymerase III alpha and DNA gyrase annotations connect this group to replication initiation, DNA synthesis and chromosome topology, respectively.
- Initiator-dependent origin opening, polymerase-mediated chain extension and topological management cooperate during chromosome duplication, using a much larger set of replication proteins than shown here.
- Preparing DNA for division requires completed replication and chromosome organization as well as envelope coordination. These selected proteins alone do not establish a full replication or segregation system.
Grouped by the atlas’s curated pathway map. The table order is not a proven reaction order.
Its proteins
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| Chromosomal replication initiator protein DnaA | — | — | Mg(2+), ssDNA | 399 | Step named |
Also part of this pathway
These proteins are described under another pathway, but also take part here.
| Protein | EC | Reaction (UniProt) | Metal or cluster | Amino acids | Certainty |
|---|---|---|---|---|---|
| DNA polymerase III subunit alphaHome: DNA synthesis | 2.7.7.7 | DNA(n) + a 2'-deoxyribonucleoside 5'-triphosphate = DNA(n+1) + diphosphate | — | 1161 | Step named |
| Type 2 topoisomerase subunit AHome: Topology management | 5.6.2.2 | ATP-dependent breakage, passage and rejoining of double-stranded DNA. | — | 769 | Step named |
Origins
How could a long chromosome be kept compact and ready to be shared at division?
SMC proteins, which condense chromosomes, are among the replication-related proteins found across all domains of life.
A bacterial chromosome is about a thousand times longer than the cell. It must be folded so it fits, yet stay open enough to be read and copied, and the copies must be pulled apart before the cell divides.
From the books: Ribas de Pouplana (ed.), The Genetic Code and the Origin of Life, p. 158.
The wider question for this part of the cell: origins for copying and repairing the genome.
Sources
- Atlas pathway grouping from the VF5 reference-genome system map (Deckert et al. 1998; Braakman & Smith 2014)
Other pathways in this group: DNA damage repair · DNA synthesis · Topology management · Joining and end processing · Recombination and restart · Initiation and opening · Homologous recombination · Base excision repair · Cysteine and methionine metabolism · Not yet placed in a pathway