Studying the structure of HIV
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The structure of all retroviruses is similar, although there are some minor differences. Virus particles are far too small to see, the closest we can come to are electron micrographs. To make transmission electron micrographs, the specimen (containing virus particles) are fixed and stained with a metal-containing dye. The more dye different areas of the specimen take up, the darker they appear in the electron micrograph.
In the centre of an HIV particle, there are two molecules of RNA which together make up the genome of the virus. Associated with the RNA are two enzymes, reverse transcriptase and integrase. The genome is enclosed in a conical core consisting of the nucleocapsid proteins. Outside this is an icosahedral protein capsid, which in turn is enclosed by the matrix protein layer. The whole particle is surrounded by a lipid bilayer known as the virus envelope. The transmembrane protein penetrates through the envelope and anchors the surface glycoprotein on the outside of the particle.
To see more detail in virus particles, special imaging techniques are needed. Cryo-electron tomography makes a three dimensional reconstruction from a series of two dimensional transmission electron micrographs taken at extremely low temperatures in order to preserve the structure of the particle. The individual micrographs represent slices though the virus particle which are put together on a computer to construct a three dimensional representation with false colours added for additional clarity.
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Tags: Biology, Health, HIV/AIDS, Medicine, Microbiology, Podcast, Science, Video, Virology
Very nice!! Most impressive. Downloaded for my children (ie: MCB3024S) as we speak. Thanks!