We recently reported the cloning and sequencing of the gene encoding a 31-kDa Treponema pallidum subsp. pallidum rare outer membrane porin protein, designated Tromp1 (D. R. Blanco, C. I. Champion, M. M. Exner, H. Erdjument-Bromage, R. E. W. Hancock, P. Tempst, J. N. Miller, and M. A. Lovett, J. Bacteriol. 177:3556-3562, 1995). Here, we report the stable expression of recombinant Tromp1 (rTromp1...