SECONDARY METABOLISM of MICROORGANISM

Marlia Singgih WibowoSchool of Pharmacy ITB

Questions about Secondary Metabolism?

• What is the difference between primary metabolism and secondary metabolism?

• What is the characteristic of secondary metabolites?

• What is the function of secondary metabolites for them and for human /mankind?

• How long is the biosynthesis pathway of secondary metabolites?

• How we can manipulate the biosynthesis pathway of secondary metabolites

Secondary metabolites categorized based on :

• Chemical Structure (e.g : cyclic nitrogen group, beta-lactam group, etc)

• Producer of metabolites (e.g : mycotoxin, bakteriotoxin, etc.)

• Activity (antibiotic, immunosuppressant, etc.)

Biosynthetic pathway ofsecondary metabolites

• Simple way , with 1 product we called it “P” (end product)

A B C P

Level of P is a feedback inhibition

• Branched biosynthetic pathway, the products P1 and P2 : together or separately influenced the conversion of C to D and E

D P1A B C

E P2

multivalent feedback biosynthetic pathway, where the products P1 and P2 together

influence convertion A to B, and separately influence convertion C to D and E

D P1A B C

E P2

Diversity in secondary metabolism

• More than 50 varieties can be occurred during metabolism process from one substance produced by one microorganism

• One substance maybe consists of one or more components with similar strctures , or only a few molecules difference

• Example : anthraquinone and endocrocin, or combination of vincristin, isovincristin, rubrocristin

MeO

OH OH O

Me

Me

O

Isovincristin

H

VincristinMe

O

O

OH OH

OH

Rubrocristin

• In secondary metabolism , there are some specific metabolites produced beyond the primary metabolism

• Not all secondary metabolites produced by gathering units from primary metabolites

Specific metabolites

Secondary Metabolites with Chlor and Bromine

• Chlor (Cl) or Bromine (Br) bound covalently with the main structure, example : Chloramfenikol, Griseofulvin, Chlor-tetrasiklin, pyrolnitrine, etc.

• To evaluate the biosynthesis, radioactive Chlorine can be added into growth media, and analysed.

Substances with unusual nitrogen moiety

• Several secondary metabolites contains unusual nitrogen moieties such as nitro, nitroso, cyano, diazo, nitrilo, isonitrilo, hydroxamic acid, etc.

• Example : Azaserin, alazopeptin, borrelidin, toyocamisin, alanosin, xantocillin, isonitrin A, ferrioxamine, dll.

Substances with Phosphorous• Primary metabolites which contain

Phosphorous for example ester of phosphoric acid

• Secondary metabolites which contain fosfor, i.e. fosfonate, fosfinate, fosfonamidate, Fosfonomisin, plumbemisin B, fosforamidon

• However, these ester can be easily degraded so that they are difficult to be detected .

Organometal

• Secondary metabolites that contain metal mostly in the form of Fe (iron) complex, i.e. ferroxamine, ferricrosin, coprogen, ferroverdin (with Fe bivalent), ferrimisin A, etc.

• Other metals are : magnesium (magnesidin), Copper (bleomisin, pleomisin)

Other secondary metabolites

• with Boron : boromicyn, aplasmomicyn

• With amino acid : alanosin, azaserine, diaminosuccinic acid, Rhizobitoxin, dll

Function of secondary metabolites

• Derailed Primary Metabolism• Biochemical Appendices• Waste products, shaving from an

imperfectly functioning intermediate metabolism

• Product of detoxification mechanisms• Results of an inhibited growth• A Playing field of biochemical evolution

Biological System of microorganism has 5 important level in their development

• Intermediate Metabolism• Regulation of intermediate metabolism• Transport of substrates and metabolites• Differentiation• Morphogenesis

In these stages usually secondary metabolites are formed/ produced

Classification of secondary metabolites based on its precursor and structural

components Sugars

Glikolisis Siklus P-P

FosfoenolpiruvatSiccimic acid pathway

Nukleic acid, polysaccaride, glicoside

Derivates of sugar : glikosida, oligosakarida, aminoglikosida

Protein

aa alifatik

aa aromatic Unusual aa : oligopeptida, alkaloid

Malonil CoA

Asetoasetil CoAFatty acid

Skualen

Poliketida

Isoprenoid

Piruvat

Asetil CoA

Siklus TCA

Secondary metabolites pathway in fungi

Monosakarida

Energi

Siklus TCA

Senyawa 3 C

Piruvat

Asetil CoA

Energi

Aa aromatik

Metabolit sekunder

Gula alkohol, disakarida, polisakaridacadangan

Malonil CoA

Asamlemak

Metaboilitsekunder

Asam organik, asam amino

MevalonatKarotenoid, sterol, met.2nd

Metabolit sekunder

Metabolit sekunder

POLYKETIDE

• Poly of β-keto acid• Subunit polyketide can be :

-CH2CO- acetate-CHMeCO- propionate-CHEtCO- butirate

• If reduction process occurred in polymerization of acetate, fatty acid will be formed

Acetate polymerization

XS-CO-R & CH2-CO2-COSX

XSH + R-CO-CH2-COSX + CO2

Variation of polyketide that might be formed

• Variation 1 : form a chain of 4 units, max. 19 unit

• Variation 2 : reduction of chain to form fatty acid, then cyclication

• Variation 3 : dehydration and aromatic formation• Variation 4 : addition of other units, e.g.

propionate or butirate• Variation 5 : cyclic, lacton formation

• Variation 6 : addition of Oxygen moiety• Variation 7 : addition of C-methyl and O-

methyl• Variation 8 : modification of chain, e.g.

decarboxyilation at carboxyl end• Variation 9 : addition of atom Chlor or

Bromine• Variation 10 : Combination with other

polyketide moieties• Variation 11 : dimerisation

AMINO ACID as main structure

• secondary metabolites contained polyketide usually coloured, while contained amino acid usually colorless

• Some metabolites posses antibiotic properties

• Category : – unusual amino acid – Transformation of amino acid – Synthesis of amino acid – Synthesis at non-ribosome site – Bound with other polypeptide

Biosynthesis of penicilin and cephalosporin

L-α-aminoadipic acid L-cysteineL-valine

δ-(L-α-aminoadipyl)-L-cystein

δ-(L-α-aminoadipyl)-L-cystein-D-valine

Isopenicilin N

Penicilin N Penicilin G

Deacetoxycephalosporin C

Deacetylcephalosporin C

Penicillium chrysogenumC.Acremoneum, Streptomyces sp.

Cephalosporin C

3 precursor amino acid:

L-valine, L-cystein, L-α-aminoadipat

Siklisasi 2 tahap

Regulation of penicillin by L-lysine in Penicillium chrysogenum

α-ketoglutarat + asetil CoA

Homositrat

α-ketoadipat

α-aminoadipat

Adenil AA-semialdehid L-AA-cys-val

Saccharopine Isopenisilin N

L-lysine Penisilin G

Feedback inhibition

Prekursor