The Interaction Of Oligopeptide Drugs With DNA And The Expression Of Human Peptide Transporter 2

Oligopeptides compounds generally have strong biological activity, and most of them can be used as drugs or drug precursors. Human Peptide Transporter 2 (hPepT2) is a high-affinity and low-capacity transporter, which widely distributed in body. It transports most of the di-/tripeptides as well as various peptidyl drugs, such asβ-lactam antibiotics, angiotensin-converting enzyme inhibitors, and many other imitation peptide drugs. The research of interaction between oligopeptides and DNA can help to understand the mechanism of drug in molecular level and provide guidance for the design of more effective drugs on clinical, and has great theoretical significance and applicative value in chemistry, biology and medicine.Two-oligopeptide drugs (VPA-Tyr-Tyr, VPA-His-His) and three bio-active peptides (Tyr-Leu-Leu, Ala-Ala-Leu, Ala-Ala-Val) were synthesized by solid phase method. The crude yield was all of 85% or more. Two oligopeptide drugs were separated by RP-HPLC on C18 column respectively using acetonitrile and water as mobile phase, and were characterized by ESI-MS, IR, 1H NMR and 13C NMR.The interactions between two oligopeptide drugs and DNA were investigated by UV, fluorescence spectroscopy and agarose gel electrophoresis. The effects of different factors on the interactions were studied, including different concentrations of two oligo-peptide drugs and reaction time. The results showed that the interactions of two oligopeptide drugs with DNA mainly were insert mode accompanying by static electricity interaction, and two oligo-peptide drugs did not cause significant cleavage of double strand pUC 18 DNA.HPepT2 gene was amplified and cloned into pMD18-T vector. The target gene was retrieved and cloned into expressing vector pET-30a and transformed into E.coli BL21(DE3) and Transetta(DE3). Expession of hPepT2 was induced with different concentration of IPTG, different time and different temperature. But it can not be detected by SDS-PAGE. We should express the tarket proein by optimizing the codons or expressing partial protein sequence.