Screening and function analysis of targeted short binding peptides of Endoglin

Objective:To do screening in phage displayed 12-peptide library to seek short peptides capable of binding Endoglin detect their affinity constants.Methods:After three rounds of screening,16 phage clones were randomly selected and their affinity was identified by sandwich ELISA.The DNA sequence of positive phage clones was determined,and their speciality was identified by competitive inhibition test.We finally calculated out the affinity constants of those positive phage binding peptides by non-competitive ELISA method.Result:After three rounds of screening,the enriched phage clones were identified. 6 of 16 phage clones were identified positive by competitive ELISA,which had comparatively strong binding activity to rhEndoglin.Five sequences were obtained,and the predominant sequence was AHKHVHHVPVRL.Competitive inhibition test showed that positive phage clones had good affinity to Endoglin,with the affinity constant as(1.431±0.293)×107 mol/L.Conclusion:The rhEndoglin-binding peptides with high affinity to Endoglin can be obtained through the screening of phage random peptide library, which is beneficial to the further studies on the function of Endoglin in the early diagnosis of ovarian cancer.