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Scientists have succeeded in growing a crystal that reveals the structure of the enzyme, integrase, and this could improve the design of the integrase inhibiting drugs commonly used for AIDS treatment.

Integrase – an enzyme found in retroviruses like HIV – plays a key role in HIV infection.

“When HIV infects someone, it uses integrase to paste a copy of its genetic information into their DNA,” the researchers from Imperial College in London stated.

“Availability of the integrase structure means that researchers can begin to fully understand how existing drugs that inhibit integrase are working, how they might be improved, and how to stop HIV developing resistance to them.”

Many researchers had tried and failed for more than 20 years “to work out the three-dimensional structure of integrase bound to viral DNA”, prior to this study, they stated.

To grow a crystal of “sufficient quality to allow determination of the three-dimensional structure”, the scientists from Imperial College in London and Harvard University in Boston conducted more than 40 000 trials.

These results in seven kinds of crystals, only one of which was of high enough quality for their study.

Lead author Dr Peter Cherepanov said: “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.”

Their findings are published this week in the journal Nature.