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Research Abstracts Online
January - December 2011

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University of Minnesota Twin Cities
School of Dentistry
Department of Diagnostic and Biological Sciences

PI: Wei Zhang

Structural Studies of Viral Pathogens Using Cryo-EM and 3D Reconstruction

These researchers use cryo-electron microscopy (cryo-EM) and coordinated three-dimensional reconstruction techniques to study the macromolecular structures of bacterial phages, enveloped alphaviruses, and retroviruses. They are working on three projects using the MSI computing environment.

The first project involves 3D reconstruction of φ29 mutants to 1-2 nm resolution. The process involves employing a number of graphical and parallel computational software packages to isolate images of individual virus particles, characterize the parameters involved in microscopy, determine the orientation and origin of each virus particle, compute a reconstruction map, and dock the known atomic structures of the protein components into the reconstruction map.

In the second project, the researchers are performing structural studies of alphavirus membrane fusion in situ. Enveloped Sindbis virus infects host cells through membrane fusion of viral and cellular membranes, a process directed by the viral fusion protein E1 at low pH. In order to understand the molecular mechanism that underlines membrane fusion, virus-liposome complexes were produced at different pH conditions. Analysis and comparison of the reconstruction maps will lead to understanding the protein conformational and oligomerizational changes during such membrane remodeling process.

The third project is structural studies of human T-lymphotropic virus. This retrovirus has heterogeneous morphology. Cryo-electron tomography data are processed using software packages available through MSI for 3D reconstruction. The reconstruction map will illustrate the surface protein organization, membrane envelope and the internal protein lattices. This structural information will provide insights into the molecular mechanism of assembly process of the virus.

Group Member

Sheng Cao, Research Associate