Hi, I have been trying to find a vector which will express a protein constitutively at tunable or low levels, I am strugling to find a suitable system.
Anything IPTG induced is no good because we are trying to co express an enzyme and a substrate and the substrate will be IPTG induced. We dont want high levels of the enzyme just catalytic quantities.
it doesnt necisarily have to be constitutive if we can control it at low levels, the closest I have come to finding a suitable system has been the arabinose or the proprionate induced systems but these are both problematic for NMR studies as proprionate is metabolized and arabinose is suppressed by glucose and is not versitile when it comes to cell lines.
any help would be appreciated