Download - (8) AA Biosynthesis
-
Amino Acid BiosynthesisIntroduction
-
Essential and Non-essential Amino AcidsEssential (10)ArginineHistidineIsoleucineLeucineLysineMethioninePhenylalanineThreonineTryptophanValineNon-essentialAlanineAsparagineAspartateCysteineGlutamateGlutamineGlycineProlineSerineTyrosine
-
Importance of Balanced DietMilk: proper balance of amino acidsBeans: lysine rich; methionine poorWheat: methionine rich; lysine poor
Bioengineered Wheat: high lysine content
-
Nitrogen AcquisitionNitrogen FixationNitrate AssimilationAmmonium Assimilation
-
Nitrogen Fixation(few strains of bacteria)
-
Nitrifying Bacteria
-
Nitrate Assimilation(Green plants, some fungi and bacteria)
-
Ammonium Assimilation (1)(Carbamyl Phosphate Synthetase)
-
Ammonium Assimilation (2)(Biosynthetic Glutamate Dehydrogenase)and/or(Glutamine Synthetase)
-
Microbial Nitrogen Acquisition(Metabolic Sources of Organic Nitrogen)
Glutamate (90%)>Amino Acids (90%)
Purines (50%)
Pyrimidines (50%)
Glutamine (10%)>Amino Acids
Amino Sugars
NAD+
PABA
Purines (50%)
Pyrimidines (50%)
-
Microbial Ammonium Assimilation(High NH3)
-
Mechanism of Glutamine Synthetase
-
Microbial Ammonium Assimilation(Low NH3)
Glutamine Synthetase
Glutamate Synthase
(Glutamate Oxoglutarate Aminotransferase, GOGAT)
Glutamine + -ketoglutarate + NADPH > 2 Glutamate + NADP+
-
Microbial Ammonium AssimilationHigh [NH3]Biosynthetic Glutamate DehydrogenaseGlutamine SynthetaseLow [NH3]Glutamine SynthetaseGlutamate Synthase (Glutamate Oxoglutarate Aminotransferase, GOGAT)
-
Microbial Ammonium Assimilation(High NH3)
-
Microbial Ammonium Assimilation(Low NH3)
-
Role of Glutamate(Nitrogen Donor)
-
Role of Glutamine(Nitrogen Donor)
-
Specific Products of GlutamineHistidineTryptophanCarbamyl Phosphate (CPSII)GlucosamineATPCTP
-
Regulation of Glutamine Synthetase
-
Pathways of Nitrogen Incorporation
-
Feedback Inhibition(Nitrogen-sufficient conditions)ProductsHistidineTryptophanCarbamyl-PGlucosamineATPCTP
Nitrogen StatusAlanineSerineGlycin
-
Modulation of Enzyme Activity
Sensitivity to [NH3]Importance of Glutamine/a-ketoglutarateRatio
-
Control of Enzyme Activity(Escherichia coli Enzyme)
-
Control of Gene ExpressionGlnA = Glutamine SynthetaseNtrB = AutokinaseNtrC = Transcription Factor
-
Control of Gene Expression(NtrC Transcription Factor)
-
Nitrogen Sufficiency (Rich)(Low Expression of Glutamine Synthesis)Basal expression from P1 (weak promoter)Termination at rho-independent terminatorBasal expression from PinternalRNA polymerase (s70)
-
Control of Gene Expression(Nitrogen Sufficiency)
-
Nitrogen Limitation(Ammonia Assimilation = High Expression)Expression from P2 (strong promoter)Requires NtrCP (binds to enhancer)RNA polymerase (s54)Reads through terminatorUpregulation of ntrB and ntrC
-
Control of Gene Expression(Nitrogen Limitation)
-
Two Component Sensor-Response Regulator SystemNtrB and NtrC
-
Two Component Sensor-Response Regulator SystemsAutokinase Sensor Proteins (NtrB) (autophosphorylation of histidine residue)Sensor domainTransmitter domain (C-terminus)Response Regulators (NtrC)N-terminal receiver domainCross-regulation
-
NtrC
-
Other NtrC-Sensitive OperonsDirect effect of NtrC-P (e.g. hut operon)Indirect effect of NtrC-P
-
ConclusionComplex regulation of glutamine synthetase confirms important role in nitrogen metabolism
-
Biosynthesis of Non-essential Amino AcidsSimple Pathways
-
Alanine
-
Aspartate and Asparagine
-
Glutamate and Glutamine
-
Proline
-
Proline (continued)
-
Arginine(N-Acetylglutamate Synthase)
-
Arginine (continued)(Acetylglutamate Kinase)
-
Arginine (continued)(N-Acetyl-g-glutamyl-P Reductase)
-
Arginine (continued)(N-Acetylornithine g-Aminotransferase)
-
Arginine (continued)(Acetylornithine Deacetylase)
-
Arginine (continued)(Acetylornithine:Glutamate Acetyltransferase)
-
Arginine (continued)(Ornithine Transcarbamylase)
-
Arginine (continued)(Argininosuccinate Synthetase)
-
Arginine (continued)(Argininosuccinase)
-
Arginine Catabolism(Microorganisms)
-
Regulation of Arginine Metabolism
-
Arginine Metabolism in Microorganisms(Linear Biosynthetic Pathway)
-
Arginine Metabolism in Microorganisms(Cyclic Biosynthetic Pathway)
-
Arginine Metabolism in Microorganisms(Polyamines)
-
Arginine Metabolism in Microorganisms(Catabolism)
-
Control of Arginine MetabolismPatterns of Regulation
-
Arginine Metabolism in Escherichia coli(Properties)Scattered genes (arginine regulon)Linear biosynthetic pathwayAcetylglutamate synthase (AGS)Acetylornithinase (AO)No catabolic pathwaySingle Carbamyl-P synthetase (CPS)Alternative pathway for polyamine synthesisOrnithine Decarboxylase (ODC) orArginine Decarboxylase (ADC) and Agmatine Ureohydrolase (AUH)
-
Arginine Metabolism in Escherichia coli(Reactions)
-
Regulation of Enzyme Amount(long-term regulation)Biosynthetic enzymes: repression by arginineCPS: cumulative repression (tandem promoters)ArgininePyrimidinesADC and AUH: induction by arginine
-
Regulation of Enzyme Activity(short-term regulation)Ornithine synthesis: fbi AGS (no ornithine)CAP synthesis (CPS)Feedback inhibition by UMPActivation by ornithineOTC (no control): no ornithinePolyamines: ADH and AUH
-
Arginine Metabolism in Bacillus subtilis(Properties)Linear pathwayInducible arginase pathway (no urease)Two CPSs
-
Arginine Metabolism in B. subtilis(Reactions)
-
Regulation of Enzyme Amount(long-term regulation)Biosynthetic enzymes: repression by arginineCPSRepression of CPS-A by arginineRepression of CPS-P by pyrimidinesArginase: induction by arginineInducer = arginineNitrogen catabolite repression
-
Regulation of Enzyme Activity(short-term regulation)Ornithine synthesis: fbi of AGSCAP synthesis (CPS-A and CPS-P)Feedback inhibition of CPS-P by UMPFeedback inhibition of CPS-A by ArgOTC: inhibition by arginase (+arg)Polyamines: Ornithine Decarboxylase (ODC)
-
Arginine Metabolism in Pseudomonas aeruginosa(Properties)Cyclic pathwayInducible arginase pathway Single CPS
-
Arginine Metabolism in Pseudomonas aeruginosa(Reactions)
-
Regulation of Enzyme Amount(long-term regulation)Biosynthetic enzymes: repression by arginineCPS: cumulative repression by arginine and pyrimidinesCatabolic enzymes: induction by arginine
-
Regulation of Enzyme Activity(short-term regulation)Ornithine synthesis: fbi of AGS and AGKCAP synthesis (CPS)Inhibition by UMPActivation by ornithineOTC: inhibition by argininePolyamines: Ornithine Decarboxylase (ODC)