Architecture and self-assembly of Clostridium sporogenes and Clostridium botulinum spore surfaces illustrate a general protective strategy across spore formers
Authors
Janganan, Thamarai K.Mullin, Nic
Dafis-Sagarmendi, Ainhoa
Brunt, Jason
Tzokov, Svetomir B.
Stringer, Sandra
Moir, Anne
Chaudhuri, Roy R.
Fagan, Robert P.
Hobbs, Jamie K.
Bullough, Per A.
Issue Date
2020-07-01Subjects
Clostridium sporogenesClostridium botulinum
sporulation
Subject Categories::C510 Applied Microbiology
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Show full item recordAbstract
Spores, the infectious agents of many Firmicutes, are remarkably resilient cell forms. Even distant relatives can have similar spore architectures although some display unique features; they all incorporate protective proteinaceous envelopes. We previously found that Bacillus spores can achieve these protective properties through extensive disulfide cross-linking of self-assembled arrays of cysteine-rich proteins. We predicted that this could be a mechanism employed by spore formers in general, even those from other genera. Here, we tested this by revealing in nanometer detail how the outer envelope (exosporium) in Clostridium sporogenes (surrogate for C. botulinum group I), and in other clostridial relatives, forms a hexagonally symmetric semipermeable array. A cysteine-rich protein, CsxA, when expressed in Escherichia coli, self-assembles into a highly thermally stable structure identical to that of the native exosporium. Like the exosporium, CsxA arrays require harsh “reducing” conditions for disassembly. We conclude that in vivo, CsxA self-organizes into a highly resilient, disulfide cross-linked array decorated with additional protein appendages enveloping the forespore. This pattern is remarkably similar to that in Bacillus spores, despite a lack of protein homology. In both cases, intracellular disulfide formation is favored by the high lattice symmetry. We have identified cysteine-rich proteins in many distantly related spore formers and propose that they may adopt a similar strategy for intracellular assembly of robust protective structures.Citation
Janganan TK, Mullin N, Dafis-Sagarmendi A, Brunt J, Tzokov SB, Stringer S, Moir A, Chaudhuri RR, Fagan RP, Hobbs JK, Bullough PA (2020) 'Architecture and self-assembly of Clostridium sporogenes and Clostridium botulinum spore surfaces illustrate a general protective strategy across spore formers', MSPHERE, 5 (4), pp.e00424-2.Publisher
American Society for MicrobiologyJournal
MSPHEREAdditional Links
https://msphere.asm.org/content/5/4/e00424-20.fullType
ArticleLanguage
enISSN
2379-5042ae974a485f413a2113503eed53cd6c53
10.1128/mSphere.00424-20
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