1.Hybrid gels assembled from Fmoc-amino acid and graphene oxide with controllable properties.
Xing P1, Chu X, Li S, Ma M, Hao A. Chemphyschem. 2014 Aug 4;15(11):2377-85. doi: 10.1002/cphc.201402018. Epub 2014 Apr 30.
A supramolecular gel is obtained from the self-assembly of an ultralow-molecular-weight gelator (N-fluorenyl-9-methoxycarbonyl glutamic acid) in good and poor solvents. The gelators can self-assemble into a lamellar structure, which can further form twisted fibers and nanotubes in the gel phase. Rheological studies show that the gels are robust and rigid, and are able to rapidly self-recover to a gel after being destroyed by shear force. Fluorescence experiments reveal the aggregation-induced emission effects of the gel system; the fluorescence intensity is significantly enhanced by gel formation. Graphene oxide (GO) is introduced into the system efficiently to give a hybrid material, and the interaction between gelators-GO sheets is studied. Rheological and fluorescent studies imply that the mechanical properties and the fluorescent emission of the hybrid materials can be fine-tuned by controlling the addition of GO.
2.Molecular dynamics simulation and conformational analysis of some catalytically active peptides.
Honarparvar B1, Skelton AA. J Mol Model. 2015 Apr;21(4):100. doi: 10.1007/s00894-015-2645-x. Epub 2015 Apr 1.
The design of stable and inexpensive artificial enzymes with potent catalytic activity is a growing field in peptide science. The first step in this design process is to understand the key factors that can affect the conformational preference of an enzyme and correlate them with its catalytic activity. In this work, molecular dynamics simulations in explicit water of two catalytically active peptides (peptide 1: Fmoc-Phe1-Phe2-His-CONH2; peptide 2: Fmoc-Phe1-Phe2-Arg-CONH2) were performed at temperatures of 300, 400, and 500 K. Conformational analysis of these peptides using Ramachandran plots identified the secondary structures of the amino acid residues involved (Phe1, Phe2, His, Arg) and confirmed their conformational flexibility in solution. Furthermore, Ramachandran maps revealed the intrinsic preference of the constituent residues of these compounds for a helical conformation. Long-range interaction distances and radius of gyration (R g) values obtained during 20 ns MD simulations confirmed their tendency to form folded conformations.
3.Glutathione-triggered formation of a Fmoc-protected short peptide-based supramolecular hydrogel.
Shi Y1, Wang J1, Wang H1, Hu Y2, Chen X2, Yang Z1. PLoS One. 2014 Sep 15;9(9):e106968. doi: 10.1371/journal.pone.0106968. eCollection 2014.
A biocompatible method of glutathione (GSH) catalyzed disulfide bond reduction was used to form Fmoc-short peptide-based supramolecular hydrogels. The hydrogels could form in both buffer solution and cell culture medium containing 10% of Fetal Bovine Serum (FBS) within minutes. The hydrogel was characterized by rheology, transmission electron microscopy, and fluorescence emission spectra. Their potential in three dimensional (3D) cell culture was evaluated and the results indicated that the gel with a low concentration of the peptide (0.1 wt%) was suitable for 3D cell culture of 3T3 cells. This study provides an alternative candidate of supramolecular hydrogel for 3D cell culture and cell delivery.
4.Development of orthogonally protected hypusine for solid-phase peptide synthesis.
Song A1, Tom J1, Yu Z2, Pham V3, Tan D2, Zhang D2, Fang G4, Yu T4, Deshayes K1. J Org Chem. 2015 Apr 3;80(7):3677-81. doi: 10.1021/acs.joc.5b00110. Epub 2015 Mar 24.
An orthogonally protected hypusine reagent was developed for solid-phase synthesis of hypusinated peptides using the Fmoc/t-Bu protection strategy. The reagent was synthesized in an overall yield of 27% after seven steps from Cbz-Lys-OBzl and (R)-3-hydroxypyrrolidin-2-one. The side-chain protecting groups (Boc and t-Bu) are fully compatible with standard Fmoc chemistry and can be readily removed during the peptide cleavage step. The utility of the reagent was demonstrated by solid-phase synthesis of hypusinated peptides.
