Sequence and structural features of the ParB-CTPase fold. Credit: Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2527592122

An investigation into cellular components in bacteria has unexpectedly uncovered a feature with relevance across many life forms, paving the way for diverse research, biotechnical and medical applications.

Researchers in the group of Professor Tung Le at the John Innes Center, in collaboration with Dr. Antoine Hocher at Cambridge University, set out to probe the key protein ParB, which helps bacteria segregate replicated or "sister" chromosomes, a vital stage in cell division, and therefore vital to survival.

ParB protein acts like a molecular clamp that entraps and slides along DNA; this way multiple ParB proteins accumulate on DNA to serve as a handle to help move replicated sister chromosomes apart to each new "daughter" cell.

This field was revolutionized six years ago with the discovery that ParB binds and breaks down a small-molecule nucleotide called CTP to switch between an open and a closed clamp form, identifying ParB as the first known CTP-dependent molecular switch.

This more recent John Innes Center–led collaboration built on this discovery with a large-scale survey that reveals that the structural feature that enables CTP binding, known as the ParB-CTPase fold, extends much further than previously thought.

Combining bioinformatics and biochemistry, they show the fold is a widespread feature across many forms of life in addition to bacteria, including archaea, eukaryotes, and viruses.

The research, published in the Proceedings of the National Academy of Sciences, additionally shows that the fold is versatile—not only binding to CTP, but also to other ubiquitous nucleotides including ATP and GTP, including the first examples of GTP-binding ParB-like proteins.

This versatility suggests previously unrecognized biological functions and might open a wealth of discovery opportunities in the field.

Co-first and co-corresponding author, Dr. Jovana Kaljević, at the John Innes Center, said, "It was so exciting to see how a single protein fold, long studied in bacteria, connects a vast range of proteins found across all domains of life. This shows that evolution has repeatedly repurposed the same molecular architecture for entirely divergent functions. This finding sets the stage for a new field exploring the evolution, mechanism, and functions of ParB-like proteins across domains of life."

Dr. Kirill Sukhoverkov, a co-first author, added, "The next step for the researchers is to expand comparative, biochemical, and structural analyses to define sequence and structural features that predict whether a given Par–B–CTPase fold prefers CTP, ATP, GTP, or other small molecules".

More broadly, the research could also lead to insights into genetic regulation, biotechnology applications, and new strategies for tackling antimicrobial resistance, one of the major threats to human health in the 21st century.

More information: Jovana Kaljević et al, Versatile NTP recognition and domain fusions expand the functional repertoire of the ParB-CTPase fold beyond chromosome segregation, Proceedings of the National Academy of Sciences (2025). DOI: 10.1073/pnas.2527592122

Citation: Unexpected protein fold links bacteria, viruses, and eukaryotes in DNA management (2025, December 8) retrieved 8 December 2025 from https://phys.org/news/2025-12-unexpected-protein-links-bacteria-viruses.html

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