The photosynthetic reaction centres (RCs) of aerotolerant organisms contain a heterodimeric core, built up of two strongly homologous polypeptides each of which contributes five transmembrane peptide helices to hold a pseudo-symmetric double set of redox components. Two molecules of PscD are housed within a subunit. PscD may be involved in stabilising the PscB component since it is found to co-precipitate with FMO (Fenna-Mathews-Olson BChl a-protein) and PscB. It may also be involved in the interaction with ferredoxin [1].

1: The reaction center of green sulfur bacteria(1). Hauska G, Schoedl T, Remigy H, Tsiotis G; Biochim Biophys Acta. 2001;1507:260-277. PMID:11687219