# ANU researchers map the modular coevolution of prokaryotic GH18 chitinases

- Published: 2026-11-06 18:06 UTC
- Section: Life & Health › Biology & biochemistry
- Tags: GH18 chitinases, modular evolution, Australian National University, Nature Communications, protein architecture, catalytic domain
- URL: https://realtech.media/news/rt-dbd939cb540e1d57418d6864_anu_researchers_map/

**Biochemists analyzed domain compositions of GH18 chitinases in silico, revealing two distinct evolutionary trajectories for metabolic and developmental enzymes.**

![ANU researchers map the modular coevolution of prokaryotic GH18 chitinases](https://sgzwpqqelzmajkcubgkl.supabase.co/storage/v1/object/public/rt-media/2026/11/25fdae4e7822cf9d.jpg)
*Jun from Melbourne, Australia, Wikimedia Commons, CC BY-SA 2.0*

Biochemists from the Australian National University mapped the sequence space of prokaryotic chitinases to identify the mechanisms driving their structural diversity, according to a study published in Nature Communications [1]. By combining phylogenetics with quantitative evaluations of domain promiscuity, the team analyzed how auxiliary domains and catalytic cores coevolved across the GH18 family of multi-domain enzymes.

Chitinases serve as essential drivers of global nutrient cycling, degrading insoluble chitin polymers across varied ecosystems. Despite their prevalence, structural variations across the enzyme family have lacked a clear evolutionary explanation. To address this, the authors tracked how individual catalytic scaffolds accumulate or discard auxiliary domains to adapt to functional demands [1].

## Divergent evolutionary trajectories

The mapping revealed that prokaryotic GH18 chitinases follow two distinct evolutionary paths depending on their biological role [1]. Enzymes dedicated to environmental chitin scavenging display high modular plasticity, continuously acquiring auxiliary domains alongside structural elaborations within the catalytic core. This modularity allows the bacteria to target complex, variable chitin substrates found across natural habitats.

In contrast, chitinases responsible for specialized physiological processes follow an alternative evolutionary regime [1]. Sequences tasked with essential developmental functions fix their domain architectures over time, maintaining rigid structural compositions to satisfy specific, lineage-dependent biological requirements.

## Modular enzyme architecture

The findings establish an empirical framework demonstrating that domain accretion directly coevolves with catalytic cores in multi-domain enzymes [1]. Structural and computational investigations were supported by the MX2 beamline at the Australian Synchrotron and computational resources from the National Computational Infrastructure.

According to the authors, clarifying how auxiliary modules coordinate with catalytic frameworks provides fundamental insights into enzyme adaptation in complex biological environments [1]. This evolutionary model accounts for the wide domain heterogeneity found in prokaryotes, establishing how modular rearrangements direct enzymatic diversification.

## Sources

1. [Nature Communications](https://doi.org/10.1038/s41467-026-79280-4)

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