(BOSTON, MA) A collaborative team led by a Northeastern University professor may have altered the way we look at drug development for HIV by uncovering some unusual properties of a human protein called APOBEC3G (A3G).
In an article published in Nature Chemistry, Prof. Mark Williams and his graduate student Kathy Chaurasiya, along with several collaborators, show how these unusual properties help us to fight HIV infection.
It is well known that in response to virus infection, the body makes specific antibodies to counteract the infection. However, we are also born with another way to fight infection, namely through the action of defense proteins that are always present in our system. These proteins provide the first line of defense against invading pathogens. For example, we are all potentially protected against HIV because we have an antiviral protein called A3G. However, HIV has evolved a strategy to circumvent the activity of this protein by tricking our cells into destroying our own A3G proteins. This is where Prof. Williams's research comes into play.
A MULTI-FUNCTIONAL PROTEIN
A3G moves along a DNA strand as part of its function as an enzyme, and when it reaches a particular one of the four bases in DNA, it chemically alters the DNA, causing HIV to mutate. This was originally thought to be the only way A3G blocks HIV infection. However, some researchers found that even when A3G could not chemically alter the DNA, it still inhibited HIV. To explain this, Prof. Williams's collaborator Dr. Judith Levin from NIH, together with postdoctoral fellow Dr. Yasumasa Iwatani, proposed that A3G forms a roadblock that prevents the virus from making a DNA copy of its genome, thereby stopping HIV replication. This would require A3G to be more slow-acting, yet because the protein normally has to move fast to perform its chemical function, there seemed to be an apparent contradiction in the experimental res
|Contact: Lori Lennon|
Northeastern University College of Science