This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: Oxford University researchers have captured the step-by-step assembly of individual virus-like particles, revealing how simple molecular interactions can reliably build these complex biological structures. The results were published today (September 16) in Nature.
Understanding how viruses assemble—and what can disrupt this process—could ultimately help researchers design novel antiviral treatments, as well as engineer vaccines and other therapies. The new study provides a molecular-level view of how the protein shells associated with viruses can spontaneously and reliably assemble from their individual components, even when there are thousands of possible ways for these to fit together. The study found that the process works rather like finding a route through a maze in which only the productive turns lock into place.
Protein building blocks initially make weak, reversible connections, allowing unsuccessful arrangements to fall apart and be tried again. But when the proteins form particular closed structures, their multiple connections make them much more stable. These structures act as a small number of molecular waypoints, progressively funneling an otherwise highly complex process toward the completed particle.
A crucial moment occurs when five larger protein building blocks form a closed pentagonal ring—the first particularly stable structure in the pathway. After this step, fewer protein building blocks are needed to reach each new stable stage, allowing the assembly process to speed up. Roi Asor (Department of Chemistry and Kavli Institute for Nanoscience Discovery, University of Oxford) said, "A virus has to solve an extraordinary construction problem.
Its components somehow have to find the right arrangement among a huge number of possibilities, without a blueprint or machinery directing the process. We can now watch what happens molecule by molecule and see the physical rules that make it possible." Viruses protect their genetic material inside precisely organized protein shells called capsids. These structures can contain tens or even thousands of protein components, yet in many viruses their building blocks spontaneously assemble into the correct shape.
Scientists have studied this process for decades, but observing it directly has proved extremely difficult. Crucial intermediate structures are scarce and often short-lived, meaning that conventional experiments can show researchers what is present before and after assembly without necessarily revealing the molecular steps connecting the two. The Oxford team tackled this problem using an engineered virus-like particle made from 60 protein units.
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