Characterization and Deposition of the Proteins in the Outermost Layer of Bacillus megaterium Spore

Abstract

It was proved that three spore coat proteins of 48, 36, and 22 kDa (P48, P36, and P22) were the components of the outermost layer (OL) of Bacillus megaterium ATCC 12872 spore by analysis of the isolated OL. And it was indicated that these proteins were deposited not by disulfide bond, but by ionic and/or hydrophobic bonds on the spore. Among them, P36 and P22 were expected to be located on the very surface of the spore by immunological analysis. In the OL deficient mutant of B. megaterium ATCC 12872, MAE05, whose spore was lacking in these OL proteins and galactosamine-6-phosphate polymer, both P36 and P22 were present in the mother cell cytoplasm and deposited on the forespores, but they disappeared with the lysis of mother cells. An OL protein-releasing factor having proteolytic activity was detected in the culture supernatant at the late sporulating stage of both the wild-type and the mutant strains. But the factor could not act on the proteins of the mature spores and the forespores at tin (tn indicates n hr after the end of exponential growth) of the wild-type strain. Moreover, P36 and P22 were found in the spores of a revertant of MAE05 which could form galactosamine-6-phosphate polymer, suggesting that this sugar polymer played the role in protecting the OL proteins against the protease-like substance after the deposition.

BMQ_0737 encodes a novel protein crucial to the integrity of the outermost layers ofBacillus megateriumQM B1551 spores

“…Collectively, these analyses indicate that the B. megaterium QM B1551 spore coat and exosporium are comprised and assembled from a substantially different subset of proteins to their orthologous Bacillus counterparts. Several biochemical‐led studies aimed at characterising the B. megaterium QM B1551 spore coat were published through the 1970s to early 1990s (Imagawa et al ., , ; Nishihara et al ., ; Takubo et al ., ). Unfortunately, these studies predated the availability of virtually any B. megaterium genomic information and tools for targeted genetic manipulation.…”

Orthologues of Bacillus subtilis Spore Crust Proteins Have a Structural Role in the Bacillus megaterium QM B1551 Spore Exosporium

“…Spores of several strains of Bacillus megaterium have also been the focus of studies on exosporium morphology and composition (11)(12)(13)(14)(15)(16). The species is comprised of many strains, which form a clade within the Bacillus genus that is quite distinct from both the B. subtilis and B. cereus clades.…”