This family includes a putative two transmembrane alpha-helical region that contains glycine zipper motifs [2]. This family includes several Rickettsia genus specific 17 kDa surface antigen proteins [1].

1: Expression of the gene encoding the 17-kilodalton antigen from Rickettsia rickettsii: transcription and posttranslational modification. Anderson BE, Baumstark BR, Bellini WJ; J Bacteriol 1988;170:4493-4500. PMID:3139629

2: Transmembrane glycine zippers: physiological and pathological roles in membrane proteins. Kim S, Jeon TJ, Oberai A, Yang D, Schmidt JJ, Bowie JU; Proc Natl Acad Sci U S A. 2005;102:14278-14283. PMID:16179394