Alignment of geopilin protein sequences. In many Geobacteraceae, geopilins are split into two proteins that are thought to be translocated to the periplasm by separate systems and assembled there. Arrows indicate signal peptide cleavage sites: Pil-type for domain 1 and Sec-type for domain 2. In contrast, the duplicate geopilins and a membrane protein containing a geopilin-like sequence in P. carbinolicus each contain both domain 1 and domain 2, as do the geopilins of two Geobacteraceae.
Aklujkar et al. BMC Genomics 2012 13:690 doi:10.1186/1471-2164-13-690