Conformations of Human Immunodeficiency Virus Envelope Glycoproteins in Detergents and Styrene-Maleic Acid Lipid Particles
Rong Zhou, Shijian Zhang, Hanh T. Nguyen, Haitao Ding, Althea Gaffney, John C. Kappes, Amos B. Smith, Joseph Sodroski
Abstract
The human immunodeficiency virus (HIV) envelope glycoproteins (Envs) in the viral membrane mediate virus entry into the host cell and are targeted by neutralizing antibodies elicited by natural infection or vaccines. Detailed studies of membrane proteins rely on purification procedures that allow the proteins to maintain their natural conformation. In this study, we show that a styrene-maleic acid (SMA) copolymer can extract HIV-1 Env from a membrane without the use of detergents. The Env in SMA is more stable at room temperature than Env in detergents. The purified Env in SMA maintains many but not all of the characteristics expected of the natural membrane Env. Our results underscore the importance of the membrane environment to the native conformation of HIV-1 Env. Purification methods that bypass the need for detergents could be useful tools for future studies of HIV-1 Env structure and its interaction with receptors and antibodies.