Endospores, or spores for simplicity, are a highly resistant cell type
produced by some bacterial species under adverse conditions. Two main
protective layers contribute to the resilience of spores: the cortex, composed
of peptidoglycan, and the outermost proteinaceous coat. In Bacillus subtilis,
the coat comprises up to 80 different proteins, organized into four sublayers:
the basement layer, the inner coat, the outer coat and the crust. These
proteins are synthesized at different times during sporulation and deposited
at the spore surface in multiple coordinated waves. Central to coat formation
is a group of morphogenetic proteins that guide the assembly of the coat
components. Targeting of the coat proteins to the surface of the developing
spore is mainly controlled by the SpoIVA morphogenetic ATPase. In a second
stage, the coat proteins fully encircle the spore, a process termed encasement
that requires the morphogenetic protein SpoVID. Assembly of the inner coat
requires SafA, whereas formation of the outer coat and the crust requires
CotE. SafA interacts directly with the N terminus of SpoVID. (...)Fundação Luso-American
