Expression vectors

[Andy Phillips]

I have a number of cDNAs which I need to express in E.coli, some
for antibody production, and others for enzyme assay and characterization.
I've been sent some blurb by Invitrogen about their Xpress system.
The vectors use a polyHis metal binding tract (for purification) and
an enterokinase (=enteropeptidase) site for subsequent cleavage. This
looks, on paper, a neat system. Does anyone out there have any comments or
experience, good or bad, with this? 

Secondly, one of the cDNAs I need to express is an intrinsic membrane
protein. Are there specialist vectors for use with membrane proteins
or would the system above work OK? I realize that the protein may
not fold/insert properly and that I may need to do the purification 
in detergent and/or denaturant.

All comments appreciated.

Andy Phillips
Long Ashton Research Station
Bristol, UK
PHILLIPSA at LARS.AFRC.AC.UK