Abstract

Ming Wu, Zhen zhen Xu and Guang Chen

In this study, we reported the cloning and over- expression of a gene encoding human collagen peptide (CP6) in Escherichia coli and the establishment of a purification protocol for obtaining the recombinant protein. The collagen peptide (CP6) had a molecular weight of about 46 kDa, and CP6 expression comprised approximately 10% of the total bacterial protein expression. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed that most of the collagen peptide (CP6) existed in the soluble fractions. Purified collagen peptide (CP6) was highly soluble. By using high-performance liquid chromatography (HPLC), a CP6 yield of approximately 11.4 mg/L of Luria-Bertani (LB) broth was obtained. What’s more we performed assays with 3-(4, 5-dimethylthiazol2-yl)-2,5-diphenyltetrazolium bromide (MTT) and annexin V-fluorescein isothiocyanate/propidium iodide (annexin VFITC/PI) to investigate the cytoprotective effects of CP6 on the proliferation of UVA-damaged human keratinocyte cell line cells. The results of this study showed that CP6 could prevent UVA-induced DNA damage in cells of the spontaneously immortalized human keratinocyte cell line HaCaT.