Mass Spec Roundup: Tracking Lipids, Tangled Proteins and Tea Seedlings…

LC=CL Enables Omega Position Analysis in Lipids

Scientists have unveiled LC=CL – a software and database system that brings omega position analysis into reach for standard chromatography-coupled mass spectrometry workflows. Previously, locating the first double bond in fatty acids – crucial for understanding metabolism, enzyme activity, and disease mechanisms – was largely restricted to specialized analytical setups.

The team – from the University of Graz, the University of California, San Diego, and the University of Vienna – demonstrated the method’s sensitivity by detecting omega positions even in lipids at very low concentrations. It also revealed that cPLA2, a well-studied phospholipase, specifically converts mead acid (an omega-9 fatty acid), underscoring the method’s potential for uncovering enzyme specificities.

“Our database in concert with the developed software LC=CL makes omega positions of lipids available in routine chromatography-coupled mass spectrometry methods,” said first author Leonida Lamp. “Moreover, our method has proven to be far more sensitive than prior approaches, making omega position information accessible even for lipids in very low concentrations.”

Protein Twists and Turns

High-resolution computer simulations have reinforced the existence of a recently identified, long-lasting form of protein misfolding called non-native entanglement. This occurs when sections of a protein chain loop incorrectly – either forming when they should not or failing to form when they should – disrupting the protein’s structure and function.

Researchers at Penn State simulated folding at the atomic level for two small proteins, then for a larger, normal-sized protein. They found that while entanglement misfolds in smaller proteins were quickly corrected, those in larger proteins persisted – likely as correcting them requires multiple unfolding steps, and they can remain hidden from the cell’s quality control machinery.

The team validated their simulations experimentally by monitoring protein folding with limited proteolysis (LiP-MS) and crosslinking (XL-MS) mass spectrometry, which detected structural changes in the same regions predicted to misfold. “This research represents another step forward in our attempt to document and understand the mechanisms of protein misfolding,” said Ed O’Brien, lead author, in a press release. 

“Our aim is to translate these fundamental discoveries into therapeutic targets that could help mitigate the impacts of these disorders and even aging.”

Tea Time: Theanine Identified as Key Nutrient in Tea Seedlings

A spatial metabolomics study has charted the movement of key nitrogen and carbon compounds during early tea seedling development, revealing theanine’s dominant role as both a nutrient and possible signaling molecule.

Using MALDI-MS imaging, researchers from Anhui Agricultural University and South-Central Minzu University identified 1,234 metabolites across different tissues and growth stages. Theanine – accounting for over 80 percent of free amino acids in roots and stems at critical points – was rapidly synthesized during germination, concentrated in root meristem tissue, and then transported to the shoot tip. Sugars such as dextrin and raffinose were localized in actively growing regions, fueling root and shoot formation, while plant hormones like auxin and abscisic acid appeared in lower amounts.

The study provides a high-resolution metabolic map that could inform precision breeding for more vigorous, stress-resilient tea varieties. “Our research offers the first tissue-level view of how tea seedlings manage nutrient flows during early development,” said Qi Chen, co-corresponding author. “The dominance of theanine as a nitrogen form and its targeted distribution suggest that it may act not only as a nutrient but also as a signaling molecule.” 

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