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HIV-1 protease

by David Canner
The X-ray structure of HIV-1 protease reveals that it is composed of two symmetrically related subunits which form a tunnel where they meet. This is critical because it contains the active site of the protease, consisting on two Asp-Thr-Gly conserved sequences, making it a member of the aspartyl protease family. The two catalytic Asp's either interact with the incoming water or protonate the carbonyl to make the carbon more electrophilic for the incoming water.

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Structural flexibility of the periplasmic protein, FlgA, regulates flagellar P-ring assembly in Salmonella enterica.

H Matsunami, YH Yoon, VA Meshcheryakov, K Namba, FA Samatey. Scientific Reports 2016 doi: 10.1038/srep27399
A periplasmic flagellar chaperone protein, FlgA, is required for P-ring assembly in bacterial flagella of taxa such as Salmonella enterica or Escherichia coli. Here we present the open and closed crystal structures of FlgA from Salmonella enterica serovar Typhimurium, grown under different crystallization conditions. An intramolecular disulfide cross-linked form of FlgA caused a dominant negative effect on motility of the wild-type strain.

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Polio is still here!
Polio vaccines have been available since the 1950s, but the challenges of vaccination in remote areas of Afghanistan and Pakistan have prevented worldwide eradication. In 2022, polio was found circulating in parts of New York State, USA. The polio virus has a small RNA genome enclosed in an icosahedral capsid composed of several proteins, shown cut in half. The structures of virus capsids can be explored using free FirstGlance in Jmol.

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