Synthesis of P-32-labelled protein probes using a modified thioredoxin fusion protein expression system in Escherichia coli

摘要

The thioredoxin fusion protein expression system from invitrogen was modified so that P-32-labelled recombinant proteins can be easily obtained in large quantities for functional studies. Proteins that are prone to form the inclusion bodies can be functionally expressed as thioredoxin fusion proteins in Escherichia coli. After expression, the recombinant proteins can be easily phosphorylated with P-32-gamma ATP and the P-32-labelled protein can be obtained functionally via a mild proteolytic digestion to cleave off the thioredoxin moiety. A deletion construct of the Ah receptor nuclear translocator protein was used as an example to illustrate how this protein expression system works.