Recombinant Expression and Characterization of N-terminal 43-amino Acid Deleted Human Apolipoprotein A-I (apoA-IΔ43) and Reconstitution of High-Density Lipoprotein Nanoparticle

High-density lipoproteins (HDL) play crucial roles in cholesterol homeostasis and have emerged as promising therapeutic targets and drug delivery vehicles. This study developed an optimized protocol for recombinant expression of N-terminal 43-amino acid deleted human apolipoprotein A-I (apoA-I∆43) in Escherichia coli BL21(DE3) and subsequent reconstitution of HDL-mimetic nanoparticles. Expression optimization revealed that an induction temperature of 37°C, a 3-hour duration, and IPTG concentration of 0.1 mM yielded the highest apoA-I∆43 expression level (~20 mg/L culture). The purified apoA-I∆43 was characterized by LC-MS/MS, confirming a 185-amino acids of the expected 265-amino acid sequence. Reconstituted HDL-mimetic (rHDL) nanoparticles were successfully prepared using apoA-I∆43 and distearoyl-phosphatidylcholine (DSPC). These rHDL nanoparticles exhibited HDL-specific characteristics such as density (1.063-1.21 g/mL) and hydrodynamic diameter (11.7 ± 3.4 nm). This protocol provides a reliable platform for producing apoA-I∆43 for pharmaceutical applications and drug delivery system development.