Revision as of 10:27, 30 July 2010

Subtilin

A type 1 antimicrobial peptide [AMP] or lantibiotic produced by B. subtilis
- NB. Lantibiotic = peptide-derived antibiotics with high antimicrobial activity against various Gram-positive bacteria, including pathogenic bacteria such as propionibacteria, staphylococci, clostridia, enterococci and streptococci.
- NB. Subtilin not same as Subtilisin!!!!!
Production of subtilin involves the spa gene cluster encompassing 10 genes, spaBTCSIFEGRK

The construct above contains:

spaRK promotor
spaR (subtilin peptide antibiotic Regulation) - the 220 amino acid product of this gene usually regulates the downstream production of subtilin antibiotic. It has an N-terminal domain that can be phosphorylated and a C-terminal domian that has DNA binding properties [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T0M-4D4XNMM-4&_user=224739&_coverDate=09%2F01%2F2004&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000014659&_version=1&_urlVersion=0&_userid=224739&md5=1f421f180a48e2d68b86da579cc7f920|1]
spaK (subtilin peptide antibiotic Kinase) - this gene codes for a 325 amino acid histadine kinase peptide that phosphorylates the N-terminus of SpaR [http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6T0M-4D5KTFV-1&_user=224739&_coverDate=09%2F01%2F2004&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000014659&_version=1&_urlVersion=0&_userid=224739&md5=8d450f455463638579798872811ae5c0|2]. This activates the DNA binding ability of the C-terminus of SpaR, which in turn initiates transcription of the downstream gene. In the case of our construct, this gene is gfp.
rrnO transcriptional terminator
spaS promotor - a strong promotor inducible by upstream activation of spaRK. It can be placed in front any gene to regulate its activity.

Image from Modeling Subtilin production in Bacillus subtilis Using Stochastic Hybrid Systems. Hu et al.

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 Image from Modeling Subtilin production in ''Bacillus subtilis'' Using Stochastic Hybrid Systems. Hu et al.
-=Genes required for swarming=
-# ''comP'': Histidine sensor kinase of ComX and PhrC
-# ''comA'': Response regulator of Comp
-# ''sfp'': Active surfactin synthetase
-# ''srfA,B and C'': Surfactin synthetase
-# ''swrA,B and C'': Novel gene for swarming and not for swimming
-# ''efp'': elongation factor P
-# ''yabR and ymfl'': Contribute to proper coordinationamong cells of the swarming population but are not absolutely required for surface migration.
-# ''cheC and D'': chemotaxis protein
-# ''sigD'': transcription factor sigma D, which is required for the expression of genes activated in late phase of flagellum biosynthesis.
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