EDIII Protein from Powassan Virus

Powassan virus (POWV), first described after isolation in1958 from the brain of a fatal case of encephalitis in Powassan, Ontario, Canada, is a reemerging severe neuroinvasive tick-borne disease causing human encephalitis in the United States, Canada and Russia, and the only recognized tick-borne flavivirus endemic to North America.1,2 Though rare, infection by POWV in the United States has recently increased, with over 30 cases reported in 2017, and has a fatality rate of approximately 10%, with long-term neurological sequelae resulting in an estimated 50% of survivors.3,4

The POWV Envelope (E) structural protein is a highly conserved structure comprising the majority of the virus surface with multiple roles in infection, including host cell receptor recognition and binding, and is divided into three domains: Domain I (DI) consisting of a central beta-barrel domain; Domain II (DII) important for dimerization and virion assembly; and Domain III (DIII) characterized by an immunoglobulin-like segment.4 Studies demonstrated that the flavivirus E protein DIII (EDIII) is a primary antigenic target of specific neutralizing antibodies.5

The EDIII protein from the 1958 lineage 1 isolate, Powassan virus, strain LB (BEI Resources NR-51181) is currently in production and coming soon to the BEI Resources catalog as NR-52391, and represents the first commercially available standard for studying such emerging tick-borne infections. NR-52391 is a recombinant form of the truncated EDIII protein containing a C-terminal hexa-histidine tag, produced in a Pichia pastoris expression system and purified by immobilized-metal affinity chromatography. The mature native full-length POWV E protein is 497 residues (GenBank: NP_775516.1).

BEI Resources No.       Product Description
NR-52391 Envelope Domain III (EDIII) Protein from Powassan Virus with C-Termina lHistidine Tag, Strain LB, Recombinant in Yeast – Coming Soon



  1. Hermance, M. E. and S. Thangamani. “Powassan Virus: An Emerging Arbovirus of Public Health Concern in North America.” Vector Borne Zoonotic Dis. 17 (2017): 453-462. PubMed: 28498740.
  2. McLean, D. M. and W. L. Donohue. “Powassan Virus: Isolation of Virus from a Fatal Case of Encephalitis.” Can. Med. Assoc. J. 80 (1959): 708-711. PubMed: 13652010.
  3. Kemenesi, G. and K. Bányai. "Tick-Borne Flaviviruses, with a Focus on Powassan Virus." Clin. Microbiol. Rev. 32 (2018): e00106-17. PubMed: 30541872.
  4. “Powassan Virus Statistics & Maps.” Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, https://www.cdc.gov/powassan/statistics.html. Accessed 07 August 2020.
  5. Heinz, F. X. and K. Stiasny. “Flaviviruses and Their Antigenic Structure.” J. Clin. Virol. 55 (2012): 289-295. PubMed: 22999801.

Image:  The dorsal view of a female I. pacificus hard tick (CDC/James Gathany)

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