Essential for the localization of CwlJ in the spore coat and for spore germination triggered by calcium and dipicolinic acid (DPA). Its assembly into the spore coat is dependent on the coat morphogenetic proteins CotE and SpoIVA. Multimer. Is cross-linked by Tgl and YabG into an insoluble high-molecular-mass complex that appears very late in sporulation. Expressed during sporulation in mother cell compartment. Expression is sigma E-dependent. Three N-terminal lysines form epsilon-(gamma-glutamyl)lysine isopeptide bonds with glutamines of other spore coat proteins.