London: A research team from Imperial College London and Harvard University claims to have made a major breakthrough that would help in developing new treatments for HIV infection.
They have grown a crystal that reveals the structure of an enzyme called integrase, which is found in retroviruses like HIV.
When HIV infects someone, it uses integrase to paste a copy of its genetic information into their DNA.
During the study, researchers grew a crystal using a version of integrase borrowed from a little-known retrovirus called Prototype Foamy Virus (PFV).
They conducted over 40,000 trials, out of which they were able to grow just seven kinds of crystals. Only one of these was of sufficient quality to allow determination of the three-dimensional structure.
The researchers later studied these crystals using a giant synchrotron machine at the Diamond Light Source in South Oxfordshire and collected X-ray diffraction data from these crystals.
It enabled them to determine the long-sought structure.
The researchers then soaked the crystals in solutions of the integrase inhibiting drugs Raltegravir (also known as Isentress) and Elvitegravir and observed for the first time how these antiretroviral drugs bind to and inactivate integrase.
"It is a truly amazing story,” Nature magazine quoted Dr Peter Cherepanov, lead author of the study from the Department of Medicine at Imperial College London, as saying.
“When we started out, we knew that the project was very difficult, and that many tricks had already been tried and given up by others long ago.
“Therefore, we went back to square one and started by looking for a better model of HIV integrase, which could be more amenable for crystallization.
“Despite initially painstakingly slow progress and very many failed attempts, we did not give up and our effort was finally rewarded," he added.