Enzyme-Catalyzed Macrocyclization of Long Unprotected Peptides

A glutathione S-transferase (GST) catalyzed macrocyclization reaction for peptides up to 40 amino acids in length is reported. GST catalyzes the selective SNAr reaction between an N-terminal glutathione (GSH, γ-Glu-Cys-Gly) tag and a C-terminal perfluoroaryl-modified cysteine on the same polypeptide chain. Cyclic peptides ranging from 9 to 24 residues were quantitatively produced within 2 h in aqueous pH = 8 buffer at room temperature. The reaction was highly selective for cyclization at the GSH tag, enabling the combination of GST-catalyzed ligation with native chemical ligation to generate a large 40-residue peptide macrocycle.Massachusetts Institute of Technology (MIT startup funds)National Institutes of Health (U.S.) (grant GM101762)Damon Runyon Cancer Research Foundation (Award)Sontag Foundation (Distinguished Scientist Award)Amgen Inc. (Summer Graduate Research Fellowship

Wege zur Synthese von fullerenbasierten polyazaaromatischen Donor-Brücke-Akzeptor-Systemen und deren komplexierten Analoga : Verknüpfung des C60-Fullerenkerns mit bis(brommethyl)- oder aminofunktionalisierten bi- und tetradentaler N-Heteroaromaten...

Kleineweischede A. Wege zur Synthese von fullerenbasierten polyazaaromatischen Donor-Brücke-Akzeptor-Systemen und deren komplexierten Analoga : Verknüpfung des C60-Fullerenkerns mit bis(brommethyl)- oder aminofunktionalisierten bi- und tetradentaler N-Heteroaromaten.. Bielefeld (Germany): Bielefeld University; 2005

Synthesis, spectroscopic and electrochemical studies of a series of transition metal complexes with amino- or bis(bromomethyl)-substituted dppz-ligands: Building blocks for fullerene-based donor-bridge-acceptor dyads

Kleineweischede A, Mattay J. Synthesis, spectroscopic and electrochemical studies of a series of transition metal complexes with amino- or bis(bromomethyl)-substituted dppz-ligands: Building blocks for fullerene-based donor-bridge-acceptor dyads. JOURNAL OF ORGANOMETALLIC CHEMISTRY. 2006;691(9):1834-1844.Transition metal complexes with ligands based on dipyrido[3,2-a:2',3'-c]phenazine (dppz) have been synthesized. As metal fragments the [Ru(bpy)(2)](+), Re(CO)(3)Cl and the [Cu(PPh3)(2)](+) moieties have been used. The complexes containing amino- or bis(bromomethyl) substituted dppz ligands can be used for fullerene-based donor-bridge-acceptor dyads. The electronic absorption spectra of these complexes and of the dppz ligands were investigated. The dppz ligands show strong absorptions in the 300 and 390 nm region. An additional absorption band in the visible region (similar to 440 nm) is observed for the amino-substituted dppz-ligands. Ruthenium complexes exhibited broad absorption bands at 350-500 nm arising from intraligand-based transitions and the MLCT transition. MLCT transitions of the Re(l) and Cu(1) complexes are observed as shoulders of the stronger ligand-based absorption band tailing out to 400-500 nm. The electrochemically active complexes and ligands were studied by cyclic voltammetry and square-wave voltammetry. All ligands show one first reversible one-electron reduction located at the phenazine portion. These reductions are shifted to more positive redox potentials upon complexation. Oxidation potentials for reversible processes could be determined for the Ru2+/Ru3+ couple. For rhenium(I) and copper(I) complexes one irreversible oxidation process is observed. (c) 2005 Elsevier B.V. All rights reserved