(The) design, expression and secretion of the repetitive form of Ⅳ-HI peptide-coding sequence from recombinant E. coli cell

Abstract

Peptide GVKGDKGNPGWPGAP (called peptide IV-H1), derived from the protein sequence of human collagen type IV, triple-helix domain residues, represents an RGD-independent, cell-specific, spreading and motility promoting domain in the type IV collagen. The purpose of this study is to improve the cell adhesion activity by the repetition of the IV-H1 peptide. This kind of functional and repetitive polypeptide is biodegradable, biocompatitable and has the property of an absolute stereoregularity. With consideration of codon usage pattern in E. coli and Bacillus subtilis, the IV-H1 peptide-coding oligomeric DNA sequence was designed. For the easiness of the repetition, Nael and Smal site ae localized in the head and tail portion. For the check of the cell adhesion activity and translational stop, tyrosine code and double stop code (TAATAA) lie in separate termination oligonucleotide. The IV-H1 peptide-coding sequence (45 nucleotides) and termination oligonucleotide were chemically systhesized, purified, annealed, ligated into pUC19 cloning vector, and confirmed by the DNA sequencing. By using Nael, Smal and AlwNI restriction enzymes, the IV-H1 peptide-coding sequence was repeated up to the 33-times. By the use of pMAL-p2 expression fusion vector, the expression plasmid, p2-T7 and p2-T17, were constructed, expressed and secreted into periplasmic space in E. coli. Their apparent sizes of the artificial protein on SDS-PAGE gel were in good agreement with the calculated molucular weights (55,632 and 66,982 daltons, respectively).