| 초록 |
Overexpressed recombinant L-chain ferritin (rFL) in E. coli formed inclusion bodies. rFL was relatively thermostable at low protein concentration, but it became extremely thermolabile at high protein concentration. Glucagon · ferritin mutant (GrFL), consisting of an N-terminus fusion partner, showed enhanced thermal stability even at high protein concentration. We developed a recombinant ferritin H/L-hybrid by a direct gene fusion between H- and L-chain subunits. The presence of H-chain at the N-terminus of L-chain significantly increased the cytoplasmic solubility of the recombinant ferritin hybrid. The ferritin H/L-hybrid was biologically active with the iron storage capacity equivalent to ferritin standard. Different types of hybrid mutants were also developed using various H-chain derivatives. Comparison of the intracellular solubilities of the hybrid mutants showed that the N-terminus four helices of heavy subunit were of importance in maintaining the high solubility in E. coli cytoplasm. Consequently, the solubility of the ferritin hybrid seems to be related to such H-chain sequence that forms ferroxidase center and promotes effective intra-molecular interaction with L-chain domain of H/L-hybrid for enhancing the folding efficiency.
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