title: Photocontrol of the collagen triple helix: synthesis and conformational characterization of bis-cysteinyl collagenous peptides with an azobenzene clamp.
abstract: For the photomodulation of the collagen triple helix with an azobenzene clamp, we investigated various collagenous peptides consisting of ideal (Gly-Pro-Hyp) repeats and containing cysteine residues in various positions for a side chain-to-side chain crosslink with a suitable chromophore derivative. Comparative conformational analysis of these cysteine peptides indicated an undecarepeat peptide with two cysteine residues located in the central portion in i and i+7 positions and flanked by (Gly-Pro-Hyp) repeat sequences as the most promising for the cross-bridging experiments. In aqueous alcoholic solution the azobenzene-undecarepeat peptide formed a stable triple helix in equilibrium with the monomeric species as a trans-azobenzene isomer, whereas photoisomerization to the cis isomer leads to unfolding of at least part of the triple helix. Furthermore, the residual supercoiled structure acts like an intermolecular knot, thus making refolding upon cis-to-trans isomerization a concentration-independent fast event. Consequently, these photoswitchable collagenous systems should be well suited for time-resolved studies of folding/unfolding of the collagen triple helix under variable thermodynamic equilibria.
authors.affiliation: Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152 Martinsried, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kusebauch
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Cadamuro
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Musiol
authors.forename: Luis
authors.initials: L
authors.lastname: Moroder
authors.forename: Christian
authors.initials: C
authors.lastname: Renner
mesh_terms: D000595:Amino Acid Sequence; D001391:Azo Compounds / Q000737:chemistry*; D002942:Circular Dichroism; D003094:Collagen / Q000138:chemical synthesis*; D003545:Cysteine / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000138:chemical synthesis*; D010777:Photochemistry; D011489:Protein Denaturation; D017510:Protein Folding; D017433:Protein Structure, Secondary; D012996:Solutions / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D001391:Azo Compounds; D009842:Oligopeptides; D010455:Peptides; D012996:Solutions; C088188:glycyl-prolyl-hydroxyproline; D003094:Collagen; C009850:azobenzene; D003545:Cysteine