pBAD Vector System Concepts

The video tutorial explains the P Bad vector system, a reliable method for expressing recombinant proteins in bacteria. It details the mechanism of the system, which is based on the AIA Bad operon controlling E. coli arabinose metabolism. The gene of interest is cloned into the vector and maintained in a medium lacking arabinose to reduce plasmid instability. Gene expression is induced by adding L-arabinose, which alters the conformation of the regulatory protein AraC, activating transcription. The addition of glucose can suppress basal expression by reducing cellular cAMP levels, which is useful when the gene of interest is toxic. The video concludes with a summary of these processes.

What is the primary function of the pBAD vector system?

• To degrade proteins in bacteria

• To express recombinant proteins in bacteria

• To replicate bacterial DNA

• To inhibit bacterial growth

What is the purpose of maintaining the pBAD vector in a medium lacking arabinose?

• To enhance protein expression

• To promote bacterial growth

• To reduce plasmid instability

• To increase plasmid instability

How is the expression of the gene of interest induced in the pBAD vector system?

• By increasing temperature

• By adding glucose to the medium

• By removing arabinose from the medium

• By adding l-arabinose to the medium

What role does the araBAD promoter play in the pBAD vector system?

• It degrades the gene of interest

• It drives expression of the gene of interest and AraC

• It replicates the plasmid

• It inhibits gene expression

What happens to AraC in the absence of l-arabinose?

• It forms a loop blocking transcription

• It enhances protein synthesis

• It activates transcription

• It degrades the promoter

How does the addition of glucose affect gene expression in the pBAD vector system?

• It increases plasmid stability

• It has no effect on gene expression

• It enhances gene expression

• It suppresses basal expression

What is the effect of high cAMP levels in a glucose-free medium?

• It reduces plasmid stability

• It binds to the bBAD promoter, activating it

• It inhibits the bBAD promoter

• It degrades the gene of interest

What is the role of the catabolic activator protein complex in the pBAD system?

• It increases plasmid instability

• It degrades the gene of interest

• It binds to the bBAD promoter, enhancing activity

• It inhibits the bBAD promoter

Why is the pBAD vector system particularly useful for toxic genes?

• It degrades toxic genes

• It allows controlled expression to prevent harm

• It enhances the toxicity of the gene

• It replicates toxic genes rapidly

What is the main advantage of using the pBAD vector system in bacterial expression?

• It degrades recombinant proteins

• It inhibits bacterial growth

• It provides a reliable and controllable expression system

• It allows for uncontrolled expression of proteins