Biology Reference
In-Depth Information
4.5.RibosomalPeptides
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4.5.1. Cyanobactins
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4.5.2. Microviridins
222
4.6.Sunscreens
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4.6.1. Scytonemin
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4.6.2. Shinorine
223
4.7.Alkanes,AlkenesandTerpenes
225
4.7.1. Alkanes and alkenes
225
4.7.2. Terpenes
225
5.Conclusion
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Abstract
Cyanobacteria produce a wide range of secondary metabolites that are very diverse
in chemical structure. These metabolites show also very diverse biological activities,
including cytotoxicity, neurotoxicity, dermatotoxicity, and inhibition of proteases. The
cyanotoxins that are harmful to animals, including humans, are essentially produced
byfreshwatercyanobacteria,whilemarineandterrestrialcyanobacteriaproducesome
metabolitesthatarepromisingnewdrugs.Between2001and2010,manybiosyntheses
ofcyanobacterialsecondarymetaboliteshavebeendecipheredatthegeneticandbio-
chemicallevel.Thankstotheadventofgenomicdataoncyanobacterialgenomesand
tonewpowerfulbioinformatictools,about30clustersofgenesresponsibleforthepro-
ductionofcyanobacterialsecondarymetaboliteshavebeenidentified.Thebiosyntheses
havealsobeenstudiedin vitro,incertaincases.Forinstance,amongthecyanotoxins,the
microcystin,thecylindrospermopsin,thesaxitoxinandtheanatoxin-abiosyntheseshave
beenelucidated.Almost all cyanobacterial secondarymetabolites are theproductsof
polyketidesynthases,nonribosomalpeptidesynthasesorhybridthereof.However,ribo-
somalpeptides are alsoproducedby cyanobacteria, like the cyanobactins and recent
genomemining data suggest that thesemetabolites aremore represented than first
thought in cyanobacteria.This reviewgives anoverviewof the connectionsbetween
cyanobacterialsecondarymetabolitesand theirbiosyntheticgenes,withemphasison
themostsignificantcaseslikethecyanotoxins,sunscreens,alkanesandterpenes.
ABBREVIATIONS
A
adenylation domain
ACP
acyl carrier protein
Adda
(2
S
, 3
S
, 8
S
, 9
S
)-3-amino-9-methoxy-2,6,8-trimethyl-10-phenyldeca-4,6-dienoic acid
Ahda
3-amino-2-hydroxy-decanoate
Ahoa
(2
S
, 3
R
, 5
R
)-amino-2,5-dihydroxy-8-phenyloctanoate
Ahp
3-amino-6-hydroxy-2-piperidone
AMT
aminotransferase domain
AT
acyltransferase domain
C
condensation domain
