Canola field DNA and DGAT1 enzymes

Decoding Plant Fat: How Understanding DGAT1 Could Revolutionize Agriculture and Nutrition

Rhea Morgan in Science & Nature June 2025 • 4 min read.

"Unlock the secrets of plant fat production: Discover how groundbreaking research into DGAT1 enzymes is paving the way for healthier oils and sustainable agriculture practices."

Fats, often misunderstood, play a crucial role in both our diets and the broader agricultural landscape. Triacylglycerols (TAGs), the primary component of plant seed oils, are essential for seed germination, seedling growth, and as a nutritional source of dietary oil for humans and animals. Beyond nutrition, plant TAGs are valuable feedstocks for creating biolubricants and biodiesel, offering a sustainable alternative to petrochemicals.

Understanding how plants produce and regulate these fats is paramount. Diacylglycerol acyltransferases (DGATs) are integral membrane enzymes responsible for catalyzing the final step in TAG biosynthesis. Among these, DGAT1 has garnered significant attention due to its pivotal role in determining the amount and composition of plant oils. Recent research published in Plant Physiology sheds light on the intricate regulatory mechanisms governing DGAT1, specifically in Brassica napus (canola).

This article unpacks the groundbreaking findings concerning the N-terminal domain of DGAT1 and its impact on enzyme activity. We'll explore how this domain acts as a regulatory switch, responding to cellular signals to fine-tune fat production. Understanding these mechanisms holds the key to engineering crops with enhanced oil content and improved nutritional profiles, ultimately benefiting both agriculture and human health.

DGAT1: The Master Regulator of Plant Fat Production

DGAT1 catalyzes the final committed step in triacylglycerol (TAG) biosynthesis, using acyl-CoA and diacylglycerol to produce TAG. The enzyme's regulation is critical for determining the quantity and quality of oil produced in plant seeds. The study highlights that the N-terminal domain of DGAT1 in Brassica napus acts as a key regulatory region, modulating enzyme activity in response to changing cellular conditions.

Researchers found that the N-terminal domain, particularly amino acid residues 81-113, directly influences DGAT1 activity and acyl-CoA affinity. This region contains an allosteric site where both CoA and acyl-CoA bind, triggering conformational changes that either activate or inhibit the enzyme. The N-terminal domain is composed of an intrinsically disordered region (IDR) and a folded segment, each contributing to the regulatory process.

Allosteric Regulation: DGAT1 activity is modulated by the binding of CoA and acyl-CoA to an allosteric site located in the N-terminal domain.
Feedback Inhibition: CoA acts as a non-competitive inhibitor, reducing enzyme activity when acyl-CoA levels are low.
Homotropic Allosteric Activation: Acyl-CoA binding enhances DGAT1 activity, ensuring efficient TAG synthesis when substrates are abundant.
Dimerization: The disordered region of the N-terminal domain facilitates dimerization, which promotes positive cooperativity and enhances enzyme efficiency.

The study further elucidates the structural elements within the N-terminal domain, revealing an alpha-helix and a loop region crucial for CoA binding. Through NMR spectroscopy, researchers identified specific amino acids (R96, R97, R99, and E100) within the loop that directly interact with CoA, providing a detailed understanding of the molecular interactions governing enzyme regulation. Site-directed mutagenesis of these amino acids confirmed their importance for enzyme activity.

Implications and Future Directions

The findings from this research provide valuable insights into the regulation of DGAT1 and offer new avenues for crop improvement. By understanding the allosteric control mechanisms and the structural elements involved, scientists can develop strategies to engineer crops with enhanced oil content, improved fatty acid profiles, and increased resilience to environmental stress. This knowledge can be applied to various plant species, contributing to more sustainable and nutritious food sources.

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This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1104/pp.17.00934, Alternate LINK

Title: Diacylglycerol Acyltransferase 1 Is Regulated By Its N-Terminal Domain In Response To Allosteric Effectors

Subject: Plant Science

Journal: Plant Physiology

Publisher: Oxford University Press (OUP)

Authors: Kristian Mark P. Caldo, Jeella Z. Acedo, Rashmi Panigrahi, John C. Vederas, Randall J. Weselake, M. Joanne Lemieux

Published: 2017-08-21

Everything You Need To Know

What is the key role of DGAT1 enzymes in plant fat production, and why is it important?

DGAT1 enzymes, specifically in plants like Brassica napus (canola), play a crucial role in catalyzing the final step of triacylglycerol (TAG) biosynthesis. TAGs are essential for seed germination, seedling growth, and as a nutritional source of dietary oil. Recent research highlights the N-terminal domain of DGAT1 as a key regulatory region, modulating enzyme activity in response to cellular conditions. Manipulation of DGAT1 activity can thus influence the quantity and quality of plant oils, with implications for both nutrition and sustainable agriculture, potentially reducing reliance on petrochemicals by enhancing TAG production for biolubricants and biodiesel.

How does the N-terminal domain of DGAT1 regulate enzyme activity in response to cellular conditions?

The N-terminal domain of DGAT1 features an allosteric site where CoA and acyl-CoA bind. CoA acts as a non-competitive inhibitor, reducing enzyme activity when acyl-CoA levels are low, thereby exerting feedback inhibition. Conversely, acyl-CoA binding enhances DGAT1 activity through homotropic allosteric activation, ensuring efficient TAG synthesis when substrates are abundant. This regulatory mechanism allows DGAT1 to fine-tune fat production based on the availability of substrates, responding dynamically to changing cellular conditions. Dimerization, facilitated by the disordered region of the N-terminal domain, also enhances enzyme efficiency through positive cooperativity.

How did researchers pinpoint the specific amino acids involved in CoA binding within the N-terminal domain of DGAT1, and why is this significant?

NMR spectroscopy was used to identify specific amino acids within the loop region of the N-terminal domain (R96, R97, R99, and E100) that directly interact with CoA. Site-directed mutagenesis of these amino acids confirmed their importance for DGAT1 enzyme activity. These findings provide a detailed understanding of the molecular interactions governing enzyme regulation. It demonstrates how specific structural elements within DGAT1 contribute to its function and regulation, opening possibilities for targeted engineering to enhance oil production or modify fatty acid profiles.

What are the potential implications of understanding DGAT1 allosteric control mechanisms for crop improvement and nutrition?

Understanding the allosteric control mechanisms of DGAT1, especially the N-terminal domain's regulatory function, offers avenues for crop improvement. By manipulating DGAT1, crops can be engineered with enhanced oil content, improved fatty acid profiles, and increased resilience to environmental stresses. This knowledge is broadly applicable across various plant species, contributing to more sustainable and nutritious food sources. However, the research does not explore the environmental impacts of increased oil production, or the effect of potential changes to the wider plant metabolome.

Beyond nutrition, what other important applications do triacylglycerols (TAGs) have, and how does DGAT1 research contribute to these areas?

Triacylglycerols (TAGs) are not only vital as the primary component of plant seed oils, essential for seed germination, seedling growth, and human and animal nutrition, but they also serve as valuable feedstocks for creating biolubricants and biodiesel. This dual role positions TAGs as a cornerstone for both nutrition and sustainable energy solutions, potentially reducing our dependence on petrochemicals. The research focuses on DGAT1, but doesn't cover other DGAT enzymes involved in TAG biosynthesis, or how these different enzymes interact to determine the final oil composition. Furthermore, the article does not touch on potential trade-offs, such as reduced growth or yield, when increasing oil production.