OBJECTIVETo economically obtain the Abeta peptide for Alzheimer's disease (AD) research by expressing the Abeta peptide fused with the maltose binding protein (MBP) possessing high solubility in E.coli.

METHODSThe cDNA-coding sequence of Abeta peptide was modified by the addition of a BamH I site at the 5' end and a Hind III site at the 3' end using PCR. The modified sequence was ligated into the maltose-binding protein (MBP) fusion expression vector pMAL-c2 containing an thrombin cleavage site, which was transformed into competent E.coli DH5alpha cells. After identification of the single clones by PCR and DNA sequencing, the recombinant plasmid was transformed into E.coli TB1 and induced to express MBP-Abeta fusion protein. The expressed fusion protein was purified using amylose resin column and identified by SDS-PAGE and Western blotting.

RESULTSThe result of DNA sequencing verified the consistency between the inserted sequence and Abeta (1-42) sequence. SDS-PAGE electrophoresis showed that MBP-Abeta fusion protein was highly expressed in E.coli TB1, and Western blotting demonstrated that the purified fusion protein and the separated Abeta peptide could be recognized by specific anti-Abeta (22-35) antibody.

CONCLUSIONMBP-Abeta fusion protein highly expressed in E. coli TB1 cells with enhanced solubility and the separated Abeta peptide with good immunogenicity obtained may lend support to AD research.