EUROPE: Researchers report important step in bacterial DNA replication in the prestigious journal Nature. Imagine a traffic accident with a 20 tone truck colliding with a small car. It can be a head-on or a rear-end collision. Does it matter which direction the car is facing, and what chance does it have of stopping the truck?
Now let’s scale this imaginary scene down a billion-fold and on this occasion the truck moving at super high speed is the molecular machinery that copies the DNA in cells that are soon to divide and the car is a roadblock that never ever stops the truck when it is hit from behind. No surprise there!
But when the car is hit from the front, it can stop the truck dead within a few centimetres. But it only does this half of the time. The other half of collisions result in the truck continuing without even slowing at all, as if the car wasn’t there at all.
A team of scientists, including four researchers from UOW, have now reported in the prestigious journal, Nature, how at the molecular level in the bacteria cell the “car” (also known as the replication terminator protein Tus) stops the “truck” only when it faces in one direction, and why it does it only half of the time.
The answer lay in a careful study of the effect of changes in the structure of Tus as it is bound to Ter, the DNA sequence it recognises. Both Tus and Ter were systematically changed in small ways and the effects on the strength of their interactions, their atomic structures, and the efficiency at which the Tus-bound blocks the DNA replication machinery were studied and correlated. This required the use of three different techniques in a collaborative effort among three research groups.
Solving this puzzle of the ‘truck’ and ‘car’ scenario at the molecular level is another significant step in generally understanding how DNA gets replicated in cells. It’s all part of unravelling the molecular mechanisms of DNA replication and providing the fundamental knowledge required to understand disease mechanisms and antibiotic resistance.
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