Trp operon

Microbial genetics

1. TRP OPERON Dr. P. Suganya Assistant Professor Sri Kaliswari College (Autonomous) Sivakasi

2. OPERN An operon is a group of closely linker structural genes and associated control genes which regulate the genetically controlled metabolic activity. SRTUCTURE OF TRP OPERON Tryptophan operon is E.coli is response for the biosynthesis Of tryptophan amino acids is the cell from the initial precursor Chorisinic acid the synthesis of amino acid tryptophan is carried Out by 5 enzyme. STRUCTURAL GENES The genes encoding there enzyme are form adjacent to one another is succession and the named are as Trp E, Trp D, Trp C, Trp B and Trp A The genes Trp E is the first to be translated.

3. PR Trp Ptrp O L TrpE TrpD TrpC TrpB TrpA DNA Promoter For Repressor Repressor Gene Promoter Operator Leader sequence Trp Operon

4. Chorisinic Acid Anthranilate synthase Trp E Anthranilic acids Anthranilate synthase II Trp B Phosphorinyl anthrosnitic Acid Trp C Carbonyl Phenyl Amino 1 – Deoxyribose Phosphate Indole 3 – glycerol (1) synthase Indole 3 – glycerol 5 Tryptophan Tryptophan synthesis Trp B Trp A

5. CONTOL OR REGULATORY GENES These control the activity of structure genes either by induction as suppression. PROMOTER GENES Is a segment of DNA at which RNA Polymerase binds and initiate the transcription of the structure genes. OPERATOR GENES Is a segment of DNA at which the polymerase binds to it and control the Transcription of form structure gives.

6. LEADER GENES Trp has a regulatory site present between promoter/operator and the first structure Genes Trp E called Leader Sequences. Which is transcript into mRNA. which is 16210kg

7. REGULATIONMECHANISMS OF TRYPHTOPHAN OPERON IN E.coli P R Trp Ptrp O L TrpE TrpD TrpC TrpB TrpA DNA Promoter For Repressor Repressor Gene Promoter Operator Leader sequence mRNA Trp R 5’ 3’ P Inactive Form Of repressor Protein Active Form Of Repressor Negative Regulator T B Presence Of Trp Operon

8. EVENTS When The Trp present tryptophan binds to the repressor molecules the activated repressor Binds to the operator and the trp operon is repressor.

9. PR Trp Ptrp O L TrpE TrpD TrpC TrpB TrpA DNA Promoter For Repressor Repressor Gene Promoter Operator Leader sequence 3 ’ 5’ Trp R - mRNA Inactive Form Of Repressor RNA Polymerase 3’ 5’ L E D C B Leader Peptide Anthranilate synthase I Anthranilate Synthase II Tryptophan Synthase B Protein Tryptophan Synthase Protein

10. EVENTS When the tryptophan in absolute Repressor solved Binds To Operator Operon activity transcribes mRNA ALTERATION The important element of the Trp operon the leader sequence which is 160bp in size , control The expression of the trp operon through a process called alternation this sequence has 4 domain.

11. FUNCTION OF THE GENES Trp Operon Genes Genes Function P/O Promoter , Operator sequence Is found In The Promoter Trp L Leader sequence Alternator (A) Sequence Found In The Leader Trp E Operons For The Anthranilate Synthesis subunit I Trp D Genes For Anthranilate synthesis Subunit II Trp C Genes To Indole Glycerol Phosphate synthesis Trp B Operon For Tryptophan Synthesis Subunit B Trp A Genes For Tryptophan Synthesis Subunit Alpha

12. THANK YOU