Scientists have found a molecule that interferes with the formation of HIV, which they hope can lead to new drugs.
HIV invades and infects cells
Current treatments involve a combination of drugs that block the activity of proteins crucial for the production and entry of HIV into cells.
However, the virus is learning how to dodge these, making it increasingly important to find new HIV drugs.
Although the work in Nature Structural & Molecular Biology is very early, HIV experts said it did hold promise.
However, it is still extremely important that people protect themselves against catching the virus in the first place, said the HIV charity Terrence Higgins Trust.
More than 40 million people worldwide have HIV.
The virus is released from infected cells as an immature, non-infectious particle with an outer shell composed of proteins call Gag.
To become infectious, it has to rid itself of Gag by splitting these proteins into smaller ones, called capsid.
Dr Hans-Georg Kräusslich and his team at Heidelberg University, Germany, working with UK researchers at the University of Southampton, found a molecule, called capsid assembly inhibitor (CAI), that binds to capsid and prevents it interacting with other capsid proteins.
This could be a pathway for stopping HIV from becoming infectious, they believe.
In a separate study published in the same journal, Dr Kräusslich, working with colleagues in France, were able to show in three-dimensional detail how CAI interferes with capsid interactions.
Armed with this knowledge, it may be possible for scientists to eventually make a drug that takes on the same shape and function of CAI to block HIV.
Lisa Power, head of policy at the Terrence Higgins Trust, said: "New discoveries like this, which may eventually lead to a new type of treatment in the fight against HIV, are always welcome.
"However, this is a long way off from any treatment that would be effective in humans.
"Our message continues to be that people should use condoms in every sexual encounter, because prevention is better than any treatment."