Pikromycin
Encyclopedia
Pikromycin was studied by Brokmann and Hekel in 1951 and is the first antibiotic macrolide to be isolated.
Pikromycin is synthesized through a type I polyketide synthase
system in Streptomyces venezuelae
, a species of Gram-positive
bacterium in the Streptomyces genus.
Pikromycin is derived from narbonolide, a 14-membered ring macrolide.
Along with the narbonolide backbone, pikromycin includes a desosamine sugar and a hydroxyl group. Although Pikromycin is not a clinically useful antibiotic, it can be used as a raw material to synthesize antibiotic ketolide compounds such as ertythromycins and new epothilones.
In Figure 1, each circle corresponds to a PKS mutilifuctional protein, where ACP is acyl carrier protein, KS is keto-ACP synthase, KSQ is a keto-ACP synthase like domain, AT is acyltransferase, KR is keto ACP reductase, KR with cross is inactive KR, DH is hydroxyl-thioester dehydratase, ER is enoyl reductase, TEI is thioesterase domain I, TEII is type II thioesterase.
Des corresponds to the enzymes utilized in desosamine biosynthesis and transfer, which include DesI-DesVIII.
Figure 2 represents the desosamine deoxyamino sugar biosynthetic pathway. DesI-DesVI (des locus of pikromycin PKS) encodes all the enzymes needed to obtain TDP-desoamine from TDP-glucose. DesVII and DesVIII activities transfer desoamine to narbonolide and narbomycin is obtained. PikC cytochrome P450 hydrolase catalyzes the hydroxylation of narbomycin to obtain pikromycin.
Pikromycin is synthesized through a type I polyketide synthase
Polyketide synthase
Polyketide synthases are a family of multi-domain enzymes or enzyme complexes that produce polyketides, a large class of secondary metabolites, in bacteria, fungi, plants, and a few animal lineages...
system in Streptomyces venezuelae
Streptomyces venezuelae
Streptomyces venezuelae is a species of soil-dwelling Gram-positive bacterium of the genus Streptomyces.S. venezuelae is filamentous...
, a species of Gram-positive
Gram-positive
Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...
bacterium in the Streptomyces genus.
Pikromycin is derived from narbonolide, a 14-membered ring macrolide.
Along with the narbonolide backbone, pikromycin includes a desosamine sugar and a hydroxyl group. Although Pikromycin is not a clinically useful antibiotic, it can be used as a raw material to synthesize antibiotic ketolide compounds such as ertythromycins and new epothilones.
Biosynthesis
The pikromycin polyketide synthase of Streptomyces venezuelae contains four polypeptides: PikAI, PikAII, PikAIII, and PikAIV. These polypeptides contain a loading module, six extension molecules, and a thioesterase domain that that terminated the biosynthetic procedure.In Figure 1, each circle corresponds to a PKS mutilifuctional protein, where ACP is acyl carrier protein, KS is keto-ACP synthase, KSQ is a keto-ACP synthase like domain, AT is acyltransferase, KR is keto ACP reductase, KR with cross is inactive KR, DH is hydroxyl-thioester dehydratase, ER is enoyl reductase, TEI is thioesterase domain I, TEII is type II thioesterase.
Des corresponds to the enzymes utilized in desosamine biosynthesis and transfer, which include DesI-DesVIII.
Figure 2 represents the desosamine deoxyamino sugar biosynthetic pathway. DesI-DesVI (des locus of pikromycin PKS) encodes all the enzymes needed to obtain TDP-desoamine from TDP-glucose. DesVII and DesVIII activities transfer desoamine to narbonolide and narbomycin is obtained. PikC cytochrome P450 hydrolase catalyzes the hydroxylation of narbomycin to obtain pikromycin.