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Chemical Conjugation of Linear and Cyclic RGD Moieties to a Recombinant Elastin‐Mimetic Polypeptide ‐ A Versatile Approach towards Bioactive Protein Hydrogels
Author(s) -
Kaufmann Doris,
Fiedler Anne,
Junger Andreas,
Auernheimer Jörg,
Kessler Horst,
Weberskirch Ralf
Publication year - 2008
Publication title -
macromolecular bioscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.924
H-Index - 105
eISSN - 1616-5195
pISSN - 1616-5187
DOI - 10.1002/mabi.200700234
Subject(s) - chemistry , native chemical ligation , self healing hydrogels , lysine , peptide , hexanoic acid , chemical modification , linker , ligand (biochemistry) , stereochemistry , amino acid , solid phase synthesis , combinatorial chemistry , conjugated system , bioconjugation , chemical synthesis , biochemistry , polymer chemistry , organic chemistry , in vitro , receptor , polymer , computer science , operating system
An elastin‐mimetic polypeptide, (EMM) 7 , with the amino‐acid sequence GRDPSS [VPGVG VPG K G VPGVG VPGVG VPG E G VPGIG] 7 was used for chemical conjugation of various integrin ligands (RGD peptides) to prepare bioactive hydrogels. The chemical approach involved (1) chemical protection of lysine residues with Fmoc or Boc groups, (2) chemical ligation of a protected linear or cyclic RGD ligand, with or without a hexanoic‐acid spacer to the glutamic acid residue, (3) deprotection of the lysine functionalities and the RGD moieties and (4) cross‐linking to form a bioactive hydrogel. 1 H NMR spectroscopy was used to quantify the multiple steps in the reaction. The chemical protection was found to be between 65 and 93% for Fmoc and Boc, respectively. The ligands studied included linear RGD cell‐binding [HFGRGDSOH (1‐l‐RGD), HAhxFGRGDSOH (2‐AhxFGRGDS) and a cyclic H 2 N(CH 2 ) 6 COHN cyclo (RGDfK) (HAhx c (RGDfK)) peptide also with a hexanoic‐acid spacer. Cell adhesion with mouse osteoblast cells was dependent on the ligand type, ligand density and the use of a spacer.