Scientists have discovered iris-like pores in the virus’s protein shell that open to suck in the building blocks it needs to copy its genetic material.

A team of scientists has identified an essential element of HIV as a potential new drug target. Publishing their findings in the journal Nature, researchers studied the virus’s outer protein shell, known as the capsid.

After HIV enters a cell, it must copy its genetic material, which comes in the single-stranded form of RNA, so it can make double-stranded DNA. The virus hides inside the capsid while it does this.

The researchers wanted to know how the virus obtains the building blocks, called nucleotides, it needs to copy its RNA. So they examined the atomic structure of the capsid in different states while manufacturing mutant versions of HIV to see how such changes to the virus altered the infection process. They found that there are pores in the capsid that resemble an eye’s iris, opening and closing. These pores allow HIV to draw in the nucleotide genetic building blocks very quickly while keeping out molecules the virus does not need. Such a covert system helps the virus evade the immune system.

Next the investigators designed a molecule, called hexacarboxybenzene, that could block the pores. Once the molecule did so, HIV could not copy itself and was renderded uninfectious.

The problem is that hexacarboxybenzene cannot itself penetrate the immune cells that HIV infects. So it cannot attack HIV at the point when the virus is sucking in nucleotides. The researchers are hoping to design a drug that could ultimately deliver such a pore-blocking treatment into cells. Alternatively, existing antiretrovirals might be altered to improve their ability to pass through the pores in the capsid and thus increase their effectiveness in combating the virus.

To read a press release about the study, click here.

To read the study abstract, click here.