secondary metabolites Flashcards
what is a polyketide
a hydrocarbon chain starting at 2 or 3 carbons. they are modified and lengthened by enzymes
what is PKS
polyketide synthase enzymes elongate polyketides. there are two variations
what is type 1 PKS
one large enzyme where multiple domains form one module. they are more common and produce more complex polyketides
what is type 2 PKS
several small peptides, each with a catalytic domain, which join together in a quaternary structure. they are less common and produce simpler proteins
what are the future prospects of polyketides
mutating polyketides to alter them or GM of PKS enzymes to create new products
what is a non ribosomal peptide
they have the same structure as normal peptides but are made without ribosomal translation. they are normally 8-12 amino acids, max 20, and can be linear, branched or cyclical
what enzyme makes NRPs
with non ribosomal peptide synthase NRPS which catalyse the formation of peptide bonds which make up the backbone of the peptide
what is the structure of NRPS
they are large proteins with several modules, each with 2-4 domains
what is the mechanism by which NRPs are made
one specific amino acid is added by each module of the NRPS using enzymes. if more than one enzyme is needed for one peptide (including modifying enzymes) they are clustered together in the genome
what are future prospects of NRPs
activating ‘silent’ genes in NRPS and GM of existing enzymes to generate new products
what are recent developments in NRPs
aspergillomarasmine A which reduces antibiotic resistance, the iChip which grows organisms in natural environments to maximise NRPS activity and malacidins where PCR is used to identify all NRPS genes
