[Selection and interaction of Ni2+ metal-binding peptides].

Ni2+ binding peptides were selected from phage random dodecapeptide library by metal affinity chromatography. After four rounds of biopanning, phage amplification and DNA sequencing, a group of peptide sequences were obtained. GenBank blast found no homogenous sequences, Clustal W analysis showed no motifs but they were really riched in histidines and contained di- or more histidines(his). Affinity assays of selected metal-binding phages for various metal-charged NTA resins and the experiments of E. coli suppression and detoxification gave positive results for Ni2+ binding peptides: strong affinities for Ni2+ were found for Ni2+ binding peptide displayed phages, as well as for other metals (Cu2+, Co2+, Zn2+, Cr2+, Cd2+); affinities of the binding peptides for Cu2+, Ni2+, Co2+ and Zn2+ were much higher than that of Cd2+ and Cr2+; in addition, Ni2+ binding peptides displayed phages had effects on E. coli as to enhance the tolerance and detoxification of E. coli for heavy metals when exposed to Ni2+ and Cd2+. The interactions of meal binding peptides for heavy metals were also disclosed by microscopic observation. The research offered great values for the study of the interaction between metals and peptides, as well as in other areas such as heavy metal bioremediation.