In two papers that will be concurrently published in the August edition of the journal Nature Structural and Molecular Biology (now available on-line), the researchers report the identification of a helical substructure within a superfamily of proteins, called AAA+, as the molecular "initiator" of DNA replication in a bacteria, Escherichia coli (E. coli), and in a eukaryote, Drosophila melanogaster, the fruit fly. Taken with earlier research that identified AAA+ proteins at the heart of the DNA replication initiator in archaea organisms, these new findings indicate that DNA replication is an ancient event that evolved millions of years ago, prior to when Archaea, Bacteria and Eukarya split into separate domains of life.
"The ability of a cell to replicate its DNA in a timely and faithful manner is fundamental for survival, but, despite decades of study, the structural and molecular basis for initiating DNA replication, and the degree to which these mechanisms have been conserved by evolution have been ill defined and hotly debated," said biophysicist Eva Nogales, a collaborator on the Drosophila study.
Said biochemist Michael Botchan, also a collaborator on the Drosophila study, "Our two papers fuse together a number of biophysical research techniques to take our understanding of the mechanics of DNA opening and replisome construction to a new level."
Biochemist and structural biologist James Berger, a participant in both studies a
Source:DOE/Lawrence Berkeley National Laboratory