Structural, functional, and bioinformatic analysis of G3R, a smallpox virus chemokine binding protein
Smallpox virus (variola virus) infected humans for thousands of years. Contributing factors to its virulence were immunomodulatory proteins, through which the viruses could temporarily evade the host immune system. One group of immunomodulatory proteins expressed by poxviruses are the chemokine binding proteins (CKBPs). CKBPs bind to host chemokines and control the infiltration of leukocytes into the site of infection resulting in decreased inflammation. Although these proteins were harmful when used by a virus, some might be able to be repurposed as therapeutic agents to control human inflammation.
Variola virus encodes 3 different CKBPs, among those is G3R, which is a viral CC inhibitor (vCCI). The structure of G3R was solved and revealed a β-sandwich structure. Testing of the binding of a broad range of chemokines to purified G3R showed binding of G3R to a group of chemokines. The effect of G3R on chemokine mediated chemotaxis by leukocytes was measured in vitro and the migration inhibitory effect of G3R was observed.
The origin and relation of G3R to other members of the viral CKBP family was studied using different bioinformatic analyses. Results of this work suggest that the origin of CKBPs could be an ancestral gene that has been evolved to G3R.
Generally, the structure of G3R was found to be similar to the other orthopoxviral vCCIs and capable of tight binding to a number of chemokines. With further testing and refinement it may be possible that viral proteins could have a role for diseases which are associated with highly over-expressed chemokines.
|Date||Tuesday, 12 May 2020|
|Time||12:00pm - 1:00pm|
|Event Category||Health Sciences|
|Location||Zoom meeting. Details and link available from Department secretary.|