As a result of the current Federal government funding situation, the information on this website may not be up to date or acted upon.

The NIH Clinical Center (the research hospital of NIH) is open. For more details about its operating status, please visit

Updates regarding government operating status and resumption of normal operations can be found at

NCI scientists image proteins displayed on HIV surface

  • Resize font
  • Print
  • Email
  • Facebook
  • Twitter
  • Google+
  • Pinterest
  • Posted: July 12, 2012
NCI Press Office


Using a technique called cryo-electron microscopy, researchers at the National Cancer Institute (NCI) have been able to detect shape changes in a protein called Env that is part of HIV (the human immunodeficiency virus).  HIV infection is initiated when Env binds to receptors on host cells.  The finding appeared in the July 12, 2012, issue of PLoS Pathogens. To carry out their study, NCI scientists studied both intact HIV viruses and purified Env proteins.  The HIV and protein samples were flash-frozen to very low temperatures using methods that preserve their structure and prevent formation of crystalline ice. The frozen samples were then imaged using an electron microscope. By compiling images of the proteins viewed from many different angles, the scientists were able to construct 3-dimensional models of Env and determine the changes it undergoes when it gets activated to enter host cells.

The imaging of the HIV Env protein in its activated state revealed three helical rods at its base. Because these regions of Env are derived from amino acids that are highly conserved across most HIV strains, the researchers hypothesize that development of antibodies that target this newly discovered structure could provide effective strategies to block HIV infection by attacking it at a highly vulnerable state prior to its entry into a cell. To read more about research from this lab, please go to

Most text on the National Cancer Institute website may be reproduced or reused freely. The National Cancer Institute should be credited as the source and a link to this page included, e.g., “NCI scientists image proteins displayed on HIV surface was originally published by the National Cancer Institute.”

Please note that blog posts that are written by individuals from outside the government may be owned by the writer, and graphics may be owned by their creator. In such cases, it is necessary to contact the writer, artists, or publisher to obtain permission for reuse.

We welcome your comments on this post. All comments must follow our comment policy.