Molecular modeling suggests structural consequences of an early protein mutation that promoted viral transmission.
RIKEN researchers discovered that an early mutation (D614G) in the SARS-CoV-2 virus may have contributed to its rapid spread by altering the spike protein's shape, improving the virus's ability to adapt to human hosts. The finding could help inform the development of next-generation vaccines and antiviral drugs.
The rapid spread of COVID-19 may have been partly due to changes in the structure of the SARS-CoV-2 virus wrought by an early mutation in its genome, a detailed analysis by RIKEN researchers suggests. The finding could help inform the development of next-generation vaccines and antiviral drugs.
Yuji Sugita of the RIKEN Center for Computational Science (R-CCS) and Hisham Dokainish, who was at R-CCS at the time of the study, investigated the effect of mutations on viral structure. They did this by simulating the atomic positions of molecules found in different forms of the virus's important spike protein—a tool coronaviruses use to bind and enter human cells.
They found that the substitution of a single amino acid altered this protein's shape, helping SARS-CoV-2 to adapt to human hosts. This finding demonstrates how even tiny mutations—swapping a single amino acid in this case—can greatly affect protein dynamics.
To understand why the mutation proved so advantageous to the virus, the pair ran detailed simulations of the protein's structure and stability. Their analysis—done using the RIKEN Fugaku supercomputer, one of the fastest in the world—revealed how the mutation (known as D614G) breaks an ionic bond with a second subunit of the Spike protein. It also changes the shape of a nearby loop structure, which alters the orientation of the entire protein, locking it into a form that makes it easier for the virus to enter cells (Fig. 1).
"A single and local change in an interaction within the molecule caused by a single mutation could affect the global structure of the spike protein," explains Sugita, who is additionally affiliated with the RIKEN Center for Biosystems Dynamics Research. The resulting mutant proved better at replicating and transmitting between human hosts, and the D614Glineage quickly outcompeted its ancestral lineages and spread across the globe. It remains a fixture of every dominant variant that has followed.
Sugita's team is now performing similar investigations of adaptive viral mutations that arose later in the course of the pandemic, including those found in the Omicron variant.
"Information obtained from our molecular dynamics simulations should help increase the opportunities for us to find effective drugs and other medicines," he says.

News
How nanomedicine and AI are teaming up to tackle neurodegenerative diseases
When I first realized the scale of the challenge posed by neurodegenerative diseases, such as Alzheimer's, Parkinson's disease and amyotrophic lateral sclerosis (ALS), I felt simultaneously humbled and motivated. These disorders are not caused [...]
Self-Organizing Light Could Transform Computing and Communications
USC engineers have demonstrated a new kind of optical device that lets light organize its own route using the principles of thermodynamics. Instead of relying on switches or digital control, the light finds its own [...]
Groundbreaking New Way of Measuring Blood Pressure Could Save Thousands of Lives
A new method that improves the accuracy of interpreting blood pressure measurements taken at the ankle could be vital for individuals who are unable to have their blood pressure measured on the arm. A newly developed [...]
Scientist tackles key roadblock for AI in drug discovery
The drug development pipeline is a costly and lengthy process. Identifying high-quality "hit" compounds—those with high potency, selectivity, and favorable metabolic properties—at the earliest stages is important for reducing cost and accelerating the path [...]
Nanoplastics with environmental coatings can sneak past the skin’s defenses
Plastic is ubiquitous in the modern world, and it's notorious for taking a long time to completely break down in the environment - if it ever does. But even without breaking down completely, plastic [...]
Chernobyl scientists discover black fungus feeding on deadly radiation
It looks pretty sinister, but it might actually be incredibly helpful When reactor number four in Chernobyl exploded, it triggered the worst nuclear disaster in history, one which the surrounding area still has not [...]
Long COVID Is Taking A Silent Toll On Mental Health, Here’s What Experts Say
Months after recovering from COVID-19, many people continue to feel unwell. They speak of exhaustion that doesn’t fade, difficulty breathing, or an unsettling mental haze. What’s becoming increasingly clear is that recovery from the [...]
Study Delivers Cancer Drugs Directly to the Tumor Nucleus
A new peptide-based nanotube treatment sneaks chemo into drug-resistant cancer cells, providing a unique workaround to one of oncology’s toughest hurdles. CiQUS researchers have developed a novel molecular strategy that allows a chemotherapy drug to [...]
Scientists Begin $14.2 Million Project To Decode the Body’s “Hidden Sixth Sense”
An NIH-supported initiative seeks to unravel how the nervous system tracks and regulates the body’s internal organs. How does your brain recognize when it’s time to take a breath, when your blood pressure has [...]
Scientists Discover a New Form of Ice That Shouldn’t Exist
Researchers at the European XFEL and DESY are investigating unusual forms of ice that can exist at room temperature when subjected to extreme pressure. Ice comes in many forms, even when made of nothing but water [...]
Nobel-winning, tiny ‘sponge crystals’ with an astonishing amount of inner space
The 2025 Nobel Prize in chemistry was awarded to Richard Robson, Susumu Kitagawa and Omar Yaghi on Oct. 8, 2025, for the development of metal-organic frameworks, or MOFs, which are tunable crystal structures with extremely [...]
Harnessing Green-Synthesized Nanoparticles for Water Purification
A new review reveals how plant- and microbe-derived nanoparticles can power next-gen water disinfection, delivering cleaner, safer water without the environmental cost of traditional treatments. A recent review published in Nanomaterials highlights the potential of green-synthesized nanomaterials (GSNMs) in [...]
Brainstem damage found to be behind long-lasting effects of severe Covid-19
Damage to the brainstem - the brain's 'control center' - is behind long-lasting physical and psychiatric effects of severe Covid-19 infection, a study suggests. Using ultra-high-resolution scanners that can see the living brain in [...]
CT scan changes over one year predict outcomes in fibrotic lung disease
Researchers at National Jewish Health have shown that subtle increases in lung scarring, detected by an artificial intelligence-based tool on CT scans taken one year apart, are associated with disease progression and survival in [...]
AI Spots Hidden Signs of Disease Before Symptoms Appear
Researchers suggest that examining the inner workings of cells more closely could help physicians detect diseases earlier and more accurately match patients with effective therapies. Researchers at McGill University have created an artificial intelligence tool capable of uncovering [...]
Breakthrough Blood Test Detects Head and Neck Cancer up to 10 Years Before Symptoms
Mass General Brigham’s HPV-DeepSeek test enables much earlier cancer detection through a blood sample, creating a new opportunity for screening HPV-related head and neck cancers. Human papillomavirus (HPV) is responsible for about 70% of [...]