3D protein complex model sheds light on barley grain dormancy

Sadie Harley

Scientific Editor

Robert Egan

Senior Editor

Researchers from Adelaide University and Plant Synthetic Biology Australia have uncovered new insights into the molecular machinery controlling the dormancy-to-germination transition in barley, potentially paving the way for improved crop varieties and better outcomes for farmers, maltsters and brewers.

The findings, published in the journal Kinases and Phosphatases, reveal the three-dimensional (3D) quaternary structure of a critical protein complex involved in controlling grain dormancy in barley.

The research builds on earlier work published in 2026 in the International Journal of Molecular Sciences, which established key genetic and structural foundations underlying the process.

Dormancy protects grain before harvest

Grain dormancy is a natural biological trait in cereal crops that prevents mature seeds from germinating, even under favorable environmental conditions.

In cereal crops such as barley, wheat and rice, dormancy is vital for preventing premature germination before harvest. However, balancing dormancy is increasingly challenging as changing climatic conditions create greater risks of preharvest sprouting, a phenomenon that can significantly reduce crop quality and yield.

The research focused on a family of enzymes known as mitogen-activated protein kinase (MAPK) cascade enzymes. These enzymes act as molecular messengers, transmitting environmental and regulatory signals through plant cells and ultimately influencing which genes are switched on or off during the transition from dormancy to germination.

Modeling a transient protein partnership

Using advanced computational and biophysical approaches, the team constructed a 3D quaternary model of a protein complex formed by MAP3K and MAP2K kinases and a bound ATP molecule, the primary energy source used by kinases.

"Enzymes are incredible—and they're everywhere," said computational biophysicist Maria Hrmova from Adelaide University's School of Agriculture, Food and Wine.

"They power biocatalysis and accelerate thousands of chemical reactions in living organisms, so understanding how these proteins interact at the molecular level is essential for understanding how grain dormancy is regulated.

"It was both challenging and fascinating to build the 3D protein complex, which represents a transient interaction between two key kinases. The resulting model defines the geometry of the ATP-binding pocket at the interface of the interacting proteins and plays a critical role in their function."

The researchers combined molecular docking, molecular dynamics simulations, evolutionary biology and artificial intelligence-based protein modeling to develop the structural models.

Structural insights could guide crop breeding

Hrmova said the findings have potential applications across agriculture and food production.

"Our new protein structural models could influence plant biotechnology, crop breeding, food production and the brewing and distilling industries," she said.

"By understanding the mechanisms that regulate grain dormancy, breeders may be able to optimize the timing of dormancy and germination while avoiding undesirable preharvest sprouting."

The research also establishes a foundation for future studies using experimental techniques such as X-ray crystallography and cryogenic electron microscopy to define MAPK enzyme complexes at atomic-level resolution.

Conserved enzymes point to essential functions

Co-author Emeritus Professor Geoff Fincher said the study had uncovered important new insights into the biology of barley.

"We were particularly intrigued by the almost complete conservation of amino acid sequences in barley MAP3K enzymes across pan-genome lines," Fincher said.

"This suggests the enzyme performs a central and possibly indispensable role in barley development and grain biology."

The researchers believe the discovery will advance pan-genome-informed crop breeding, helping scientists identify genetic variations that influence protein function and, ultimately, crop performance during a changing climate.

Publication details

Maria Hrmova et al., Quaternary Protein Model of the Barley MKK3 Enzyme in Complex with Its Candidate Upstream MAP3K Kinase and Functional Implications, Kinases and Phosphatases (2026). DOI: 10.3390/kinasesphosphatases4040030

Journal information:
International Journal of Molecular Sciences

Provided by
University of Adelaide

Citation: 3D protein complex model sheds light on barley grain dormancy (2026, November 11) retrieved 11 November 2026 from https://phys.org/news/2026-11-3d-protein-complex-barley-grain.html