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Glial-cell-line-derived neurotrophic factor (GDNF) is a protein that has therapeutic potential in the treatment of Parkinson's disease and other neurodegenerative diseases. The activity of GDNF is highly dependent on the interaction with sulfated glycans which bind at the N-terminus consisting of 19 residues. Herein, we studied the influence of different glycosaminoglycan (i.e., glycan; GAG) molecules on the conformation of a GDNF-derived peptide (GAG binding motif, sixteen amino acid residues at the N-terminus) using both experimental and theoretical studies. The GAG molecules employed in this study are heparin, heparan sulfate, hyaluronic acid, and sulfated hyaluronic acid. Circular dichroism spectroscopy was employed to detect conformational changes induced by the GAG molecules; molecular dynamics simulation studies were performed to support the experimental results. Our results revealed that the sulfated GAG molecules bind strongly with GDNF peptide and induce alpha-helical structure in the peptide to some extent., (Copyright © 2021. Published by Elsevier B.V.)

We report a novel, noncovalent hydrogel system crosslinked solely by receptor-ligand interactions between biotin and avidin. The simple hydrogel synthesis and functionalization together with the widespread use of biotinylated ligands in biosciences make this versatile system suitable for many applications. The gels possess a range of tunable physical properties, including stiffness, lifetime, and swelling. The erosion rates, unexpectedly fast compared to the kinetic parameters for biotin-avidin, are explored in terms of stretching tensions on the polymers, a concept well-known on the single-molecule level, but largely unexplored in supramolecular systems. As proof of utility, the gels were functionalized with different peptide sequences to control human mesenchymal stromal cell morphology in 3D culture., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Poly(ethylene glycol)-peptide- and glycosaminoglycan-peptide conjugates obtained by a regio-selective amino acid protection strategy are converted into cell-instructive hydrogel matrices capable of inducing morphogenesis in embedded human vascular endothelial cells and dorsal root ganglia., (Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Two amphipathic polypeptides were coordinated to the cis positions of a square planar Pt(II) complex in order to provide the metal center with two noncovalent oligomerization domains. This resulted in the formation of new metal-peptide nanoassemblies which are shown to exist as nanometer-sized spheres and fibrils. Construction of these assemblies was based on the 30-residue polypeptide AQ-Pal14 which was designed for its ability to self-assemble into the common protein oligomerization motif of a noncovalent coiled-coil, and modified to contain a metal-binding 4-pyridylalanine residue at its surface. When AQ-Pal14 was reacted with Pt(en)(NO 3) 2, a new metal-peptide complex was formed in which two AQ-Pal14 peptides were coordinated to a single metal center as determined by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electrospray ionization mass spectrometry (ESI-MS). When the reaction mixture was analyzed under nondenaturing conditions by high performance size exclusion chromatography (HPSEC), it was found that all species present eluted at the column void volume, indicating the formation of very large metal-peptide assemblies. This was verified by multiangle light scattering (MALS) which showed that the metal-peptide assemblies have a weight-averaged molecular mass and z-average root-mean-square radius of Mw = (7 +/- 4) x 10 (6) g/mol and Rz = 18 +/- 4 nm, respectively. The presence of such nanometer scale assemblies was confirmed by transmission electron microscopy and atomic force microscopy which showed the existence of both spherical and fibrillar nanostructures.

Metal coordination is used to alter the oligomerization state of a designed peptide structure. The 30-residue polypeptide AQ-Pal14Pal21contains two metal-binding 4-pyridylalanine (Pal) residues on its solvent-exposed surface and exists as a very stable two-stranded alpha-helical coiled-coil. Upon the addition of Pt(en)(NO3)2, a significant conformational change to a metal-bridged, four-helix bundle is seen.

A new class of metal-peptide nanoassemblies has been prepared by combining the principles of supramolecular coordination chemistry with those of de novo protein design., (Copyright 2004 The Royal Society of Chemistry)