[Studies on the spectral characteristics of efficient HIV-1 fusion inhibitor C22]

Acquired immune deficiency syndrome (AIDS) is increasing its negative influences on human society and economy. In the present paper, HIV-1 cell fusion peptide inhibitor C22 was expressed and purified based on the C-terminal sequence of HIV-1 membrane fusion glycoprotein gp41. The gene coding for C22 was totally synthesized using gp41 gene as a template and amplified by PCR The cloned C22 gene was confirmed by restriction endonuclease and sequence analysis and then cloned into plasmid pTMHa30-51. The prepared plasmid was transformed into E. coli BL21 (DE3) and the expressing products were analyzed on SDS-PAGE and tested with mass spectrum. The results indicated that C22 showed high HIV-1 fusion inhibiting capacity, meanwhile, with good thermal stability and water-solubility, and showed no cell toxicity in tested concentrations. The spectral characteristics were tested with circular dichroism (CD). When treated at different temperature in solution condition, the content of a helix of C22 increased at 37 degrees C while decreased sharply at 80 degrees C. The peak value changed significantly with different pH values. The content of a helix of C22 decreased as pH varied toward acid and alkali and the random coiling increased, which led to a relaxed structure. This result indicated that the C22 structure is stable with pH 6. This research may provide a theoretic foundation for the new type HIV-1 peptide inhibitor designing and spectral characteristics study.