Techniques for Measuring Stability

Absorbance (e.g. Trp, Tyr) 

Fluorescence (Trp)-difference in emission max & intensity.

CD (far or near UV) - (2o or 3o) 

NMR 

DSC (calorimetry) 

Urea gradient gels - difference in the migrating rates between F and U.

Catalytic activity 

Chromophoric or fluorophoric probes/FRET 

TLS Online TPP Program

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#Unit 2. Cellular Organization

The E. coli trp operon contains the 5 genes Trp-EDCBA for the anabolic enzymes to make the tryptophan.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Major enzyme is Tryptophan Synthase

TLS Online TPP Program

#Id: 609

#Unit 2. Cellular Organization

Major enzyme is Tryptophan Synthase whose activity is reduced when trp concentration is high.

 

TLS Online TPP Program

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#Unit 2. Cellular Organization

Trp operon is negatively regulated by two ways

1. Repression

2. Attenuation

Why is this extra control of two layers on trp operon needed? 

TLS Online TPP Program

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#Unit 2. Cellular Organization

The answer probably lies in the fact that repression of the trp operon is weak—much weaker.

TLS Online TPP Program

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#Unit 2. Cellular Organization

Repression-Trp aporepressor dimer binds high tryptophan, changes conformation with high affinity for trp operator Tryptophan is a corepressor