Scientists say they have solved a crucial puzzle about the Aids virus after 20 years of research and that their findings could lead to better treatments for HIV.

British and U.S. researchers said they have grown a crystal that enabled them to see the structure of an enzyme called integrase. The enzyme is found in retroviruses like HIV and is a target for some of the newest HIV medicines.It took more than 40,000 trials for them to come up with one a crystal of sufficiently high quality to allow them to see the three-dimensional structu re

When the human immunodeficiency virus (HIV) infects someone, it uses the integrase enzyme to paste a copy of its genetic information into their DNA.

Scientists from Imperial and Harvard university said that having the integrase structure means researchers can begin fully to understand how integrase inhibitor drugs work, how they might be improved, and how to stop HIV developing resistance to them.