Dear everyone

I need to produce a protein complex from a bacterium. The protein complex contains four proteins and all of these proteins are encoded in an operon. 

Can I clone the whole operon into a usual expression vector and express and purify the complex?

I expression vector, for example, pET, has its promoter, but can this promoter control the expression of all the four protein? In my opinion, the vector promoter can control the expression of the first (the ORF nearest to 5'-terminus) protein, but can it also control the expression of the proteins far away from it?

Best regards.  

If they are in an operon they are pretty much by definition polycistronic, so...

Hello CharonY,

Thank you for your reply.

You mean that the operon can be expressing using a usual e.coli expression vector? 

The organization of the operon and the MCS of the vector look like the figure at the following link:

 https://drive.google.com/file/d/18I2RbL_B7vV6ne89Bc1KdN5-O2xal4lk/view?usp=sharing

By this clone method, do you think all the proteins in the operon can be successfully expressed?

Thank you again.

My working hypothesis is that each protein might be expressed in slightly different amounts.  Each ribosome binding site might be different, for example.  However, I have only done a little reading on this subject.

It depends on the overall control of the system. Typically you'll find transcript levels to decline along the operon (again, for somewhat obvious reasons). However, posttranscriptional control can still yield stochiometric protein expression, if the system demands it. On the other hand there are ample examples where cells exploit non-stochiometric protein production by having elements that have to be more abundant at the start of an operon.