The 3 component trans-outer membrane electron transfer Pcc complex consisting of OmaB (periplasmic c-type cytochrome of 231 aas), OmbB (putative porin of 403 aas) and OmcB (outer membrane and extracellular c-type cytochrome of 744 aas) (Liu et al. 2014; Liu et al. 2015). OmpB, OmaB and OmcB all seem to be able to facilitate extracellular Fe³⁺ reduction (Liu Liu et al. 2015). OmpB, OmaB and OmcB all seem to be able to facilitate extracellular Fe³⁺ reduction (Liu et al. 2015). OmbB is also a member of TC porin family 1.B.80.