HIGH-YIELD PRODUCTION OF FUNCTIONALLY ACTIVE HUMAN SERUM TRANSFERRIN USING A BACULOVIRUS EXPRESSION SYSTEM, AND ITS STRUCTURAL CHARACTERIZATION

Recently, there has been much interest in expressing recombinant human serum transferrin (HST) and mutants thereof for structural and functi onal studies. We have developed a baculovirus expression system for th e rapid and efficient production of large quantities of HST (> 20 mg/l ). Like native HST, the recombinant protein can bind two ferric ions i n the presence of bicarbonate, and is actively taken up by receptor-me diated endocytosis. Secondary structure calculations from CD measureme nts indicate a content of 42% alpha-helix and 28% beta-sheet. This is the first reported use of a non-mammalian expression system to produce functional HST, and will provide a practical tool to allow expression of a wide range of HST variants for mutagenesis studies.