DNA as a “master of resource recycling”

The researchers say that their results “challenge the notion that DNA replication is uniform and consistent”:

The Molecular Horizons work has for the first time revealed the complex molecular choreography where both processes occur. The replisome can adapt how it uses SSBs [
Single-stranded binding proteins] according to how much is available….

“Until now it hasn’t been shown exactly how SSBs are used. What we have revealed is a dynamic and highly efficient process that adapts to its surrounding conditions.”…

SSB’s job is to coat the lagging strand and protect it from being attacked and broken. A broken strand can cause chromosome breakage, which can contribute to genetic disorders and intergenerational disease….

… errors are rare, occurring at a rate of 1 mistake per million base pairs, one mistake that slips past the repair mechanisms can produce a DNA sequence that, if it survives and avoids the body’s defence mechanisms, could also survive drug treatments and eventually become a superbug. As a result, understanding SSBs’ role is crucial in understanding disease and antimicrobial resistance…

“If you think of the replisome as a car, it’s a complete functional system, but we can’t really test the more intricate parts of the engine,” Dr Spenkelink said. “To do that, engineers might remove the engine and bench test it. That allows them a more detailed look at specific parts that can’t be tested in a moving car. University of Wollongong, “ DNA copying machine a master of resource recycling” at Phys.org

Paper: Recycling of single-stranded DNA-binding protein by the bacterial replisome, Nucleic Acids Research (2019). academic.oup.com/nar/advance-a … 3/nar/gkz090/5320382

Hat tip: Philip Cunningham

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See also: The amazing energy efficiency of cells A science writer compares the cell to human inventions and finds that it is indeed amazingly energy-efficient.