Health & Medicine, UK (Commonwealth Union) – A group of scientists, spearheaded by the University of Oxford, has achieved a significant breakthrough in the realm of identifying alterations in protein structures. The groundbreaking technique, outlined in a publication in Nature Nanotechnology, harnesses cutting-edge nanopore technology to pinpoint structural deviations at the level of individual molecules, even in the intricate folds of lengthy protein chains.
The human cellular framework encompasses around 20,000 genes dedicated to encoding proteins. However, the practical count of distinct proteins found within cells greatly surpasses this, with a catalog of over 1,000,000 diverse structures on record. These variations are born from the process known as post-translational modification (PTM), unfolding subsequent to a protein’s transcription from DNA. PTM introduces structural shifts, such as the addition of chemical groups or carbohydrate chains onto the constituent amino acids constituting proteins. This gives rise to an array of numerous possibilities for a single protein sequence.
These variants wield paramount significance in the realm of biology by facilitating meticulous control over intricate biological processes within individual cells. Scrutinizing this diversity could unearth a trove of invaluable insights capable of revolutionizing our grasp of cellular functionalities. However, up until now, the ability to construct all-encompassing protein compendiums has remained a challenging pursuit, as indicated by researchers of the study.
In response to this challenge, a team managed by researchers from the University of Oxford’s Department of Chemistry has effectively devised a novel method for analyzing proteins, founded upon the principles of nanopore-based sensing technology. This approach employs a directed flow of water to seize and unravel 3D proteins into linear chains, which are then threaded through minute pores—just spacious enough to allow the passage of an individual amino acid molecule. Alterations in structure are discerned through measurements of fluctuations in an applied electrical current coursing across the nanopore. Distinct molecules incite diverse disruptions in the current, affording them a distinctive feature.
The team has successfully exhibited the efficacy of this method in detecting three distinct PTM modifications—phosphorylation, glutathionylation, and glycosylation—at the granularity of single molecules, even within protein chains spanning over 1,200 amino acid residues. Notably, the approach dispenses with the need for labels, enzymes, or supplementary reagents.
According to the collective insight of the research group, this fresh technique for characterizing proteins could be seamlessly integrated into existing portable nanopore sequencing devices. This, in turn, would empower researchers to rapidly assemble exhaustive protein repositories for individual cells and tissues. Such an advancement could facilitate point-of-care diagnostics, ushering in the potential for tailored identification of specific protein variants linked to ailments such as cancer and neurodegenerative disorders.
Professor Yujia Qing of the Department of Chemistry, University of Oxford, and a contributing author of the study, says ‘This simple yet powerful method opens up numerous possibilities. Initially, it allows for the examination of individual proteins, such as those involved in specific diseases. In the longer term, the method holds the potential to create extended inventories of protein variants within cells, unlocking deeper insights into cellular processes and disease mechanisms.’
Professor Hagan Bayley of the Department of Chemistry, University of Oxford, contributing author says ‘The ability to pinpoint and identify post-translational modifications and other protein variations at the single-molecule level holds immense promise for advancing our understanding of cellular functions and molecular interactions. It may also open new avenues for personalised medicine, diagnostics, and therapeutic interventions.’
Ultimately, the scientists main aim is to use this technique to form into a small portable device in protein analysis, just like those formed by Oxford Nanopore Technologies to sequence nucleic acids. Oxford Nanopore Technologies was introduced in 2005 as a spinout firm associated with Professor Bayley’s study and established itself as a front-runner for next-generation sequencing technologies. This patented nanopore-based technology makes it possible for researchers to sequence samples faster, utilizing accessible devices, when compared to standard sequencing, which generally needs dedicated laboratories.
