This domain is found at the N-terminus of P74 occlusion-derived virus (ODV) envelope proteins which are required for oral infectivity. The envelope proteins are found in baculoviruses which are insect pathogens. The C-terminus of P74 is anchored to the membrane whereas the N-terminus is exposed to the virion surface. Furthermore P74 is unusual for a virus envelope protein as it lacks an N-terminal localisation signal sequence [1]. Also see Pfam:PF04583.

1: Evidence for proteolytic cleavage of the baculovirus occlusion-derived virion envelope protein P74. Slack JM, Lawrence SD; J Gen Virol 2005;86:1637-1643. PMID:15914841