Table 1.
Main proteins of Clostridium difficile sporulation, germination and structural components
| Germination encoded protein (locus tag, strain) | MWa | Spore localizationb | Function | Refs |
| Putative cortex lytic enzyme (CD3563, strain 630) | 19 | ND | CD3563 mutant spores germinate as wild-type spores | [62] |
| CspBA (CD2247, strain 630) | 125 | ND | Essential for processing of pro-SleC into mature SleC and spore germination; spores of a cspBAC mutant have >107 -fold lower viability than wild-type spores | [14] |
| SleC (CD0551, strain 630) | 47 | ND | Essential for spore peptidoglycan cortex degradation and germination; spores of a sleC mutant had ~ 107 -fold lower viability in presence of taurocholate | [14, 62] |
| CspC (CD2246, strain 630) | 61 | ND | Bile acid germinant receptor | [15] |
| Spore structure/morphogenesis encoded protein (locus tag, strain) | MW | Spore localization | Function or observations | Refs |
| SpoIVA (CD2629, strain 630) | 56 | Basement layer? | Essential for coat localization around the forespore and functional spore formation | [44] |
| SipL (CD3567, strain 630) | 59 | Basement layer? | Essential for coat localization around the forespore and functional spore formation; sipL mutation reduces SpoIVA levels in sporulating cells | [44] |
| CotA (CD1613, strain 630) | 34 | Exosporium | cotA mutation produces ~ 50% of spores with an amorphous structure; removed from the spore surface by sonication; essential for coat and exosporium formation; required for lysozyme, ethanol and heat resistance | [22] |
| CotB (CD1511, strain 630) | 35 | Exosporium | cotB mutant spores exhibit wild-type ultrastructure; slight effect on heat resistance | [22] |
| CotCB (CD0598, strain 630) | 21 | Coat and exosorium? | Putative manganese catalase, cotCB mutant spores exhibits wild-type ultrastructure; slight effect on heat resistance | [22] |
| CotD (CD2401, strain 630) | 21 | Exosporium | Putative manganese catalase, cotD mutant spores exhibits wildtype ultrastructure; slight effect on heat resistance; sonication removes CotD | [22] |
| CotE (CD1433, strain 630) | 81 | Exosporium | Putative peroxiredoxin chitinase, cotE mutant spores exhibits wild-type ultrastructure; removed from the spore surface by sonication; slight effect on heat resistance | [22] |
| CotF (CD0597, strain 630) | 11 | Exosporium | cotF mutant spores exhibits wild-type ultrastructure; removed from the spore surface by sonication | [22] |
| CotJB2 (CD2400, strain 630) | 11 | ND | ND | |
| CotG (CD1567, strain 630) | 27 | Exosporium | Putative manganese catalase, no mutant; removed from the spore surface by sonication | [22] |
| SodA, (CD1631, strain 630) | 28 | Coat | Putative superoxide dismutase, no role in heat, Virkon, hydrogen peroxide and ethanol resistance | [22] |
| BclA1 (CD0332, strain 630) | 67.6 | Exosporium | Localizes to the spore exosporium through its N-terminal domain (NTD); SPk-treatment removes BclA1 from the spore surface.; oriented with its NTD and C-terminal domain (CTD) inwards and outwards, respectively; has a central collagen-like domain | [19] |
| BclA2 (CD3230, strain 630) | 48.9 | Exosporium | Localizes to the spore surface through NTD; has a central collagen-like domain | [19] |
| BclA3 (CD3349, strain 630) | 58.1 | Exosporium | Localizes to the spore surface through its NTD; has a central collagen-like domain | [19] |
| CdeC (CD1067, strain 630; CDR0926; strain R20291) | 44.6 | Exosporium | Essential exosporium morphogenetic factor; SPk-treatment removes CdeC from the spore surface; required for the correct assembly of the spore coat cdeC spores have lower resistance, permeable spore inner membrane and a more hydrated spore core | [23] |
a
MW, molecular weight in kDa.
b
Abbreviations: ND, not determined; ?, indicates that location has not been clearly established.