We go through tremendous quantities of Protein A linked Sepharose
in the lab. It is expensive ($50/ml).
I've heard that protein A is easily expressed in E.coli to huge amounts
with retention of binding activity. If we could get such a vector,
we could purify enough protein and immobilize it to the Sepharose
very cheaply (with periodate oxydation method, it is basically a price
of Sepharose CL-4B, protein not counting).
50 mg/liter culture --> 2 x 5 l preps --> 5 mg/ml Sepharose --> 100 ml
sorbent which can be stored in 50% ethylene glycol at -20C essentially
forever. Sounds like a three days worth of work.
Could make a good exercize for some undergraduate student wanting
to get his/her hands on some basic biochemical techniques.
I've only seen Pharmacia vector but it needs to be modified as it does
not have a tag or a stop codon. Pharmacia itself sells rProteinA
Sepharose, so I figure this or a similar construct must be in someone's
hands. An info on Protein G expression would also be helpful.
Thanks for any hints,