TY  - JOUR
A1  - Senf, Deborah
A1  - Ruprecht, Colin
A1  - Kishani, Saina
A1  - Matic, Aleksandar
A1  - Toriz, Guillermo
A1  - Gatenholm, Paul
A1  - Wagberg, Lars
A1  - Pfrengle, Fabian
T1  - Tailormade polysaccharides with defined branching patterns
BT  - Enzymatic polymerization of arabinoxylan oligosaccharides
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - The heterogeneous nature of non-cellulosic polysaccharides, such as arabinoxylan, makes it difficult to correlate molecular structure with macroscopic properties. To study the impact of specific structural features of the polysaccharides on crystallinity or affinity to other cell wall components, collections of polysaccharides with defined repeating units are required. Herein, a chemoenzymatic approach to artificial arabinoxylan polysaccharides with systematically altered branching patterns is described. The polysaccharides were obtained by glycosynthase-catalyzed polymerization of glycosyl fluorides derived from arabinoxylan oligosaccharides. X-ray diffraction and adsorption experiments on cellulosic surfaces revealed that the physicochemical properties of the synthetic polysaccharides strongly depend on the specific nature of their substitution patterns. The artificial polysaccharides allow structure-property relationship studies that are not accessible by other means.
KW  - carbohydrates
KW  - enzymes
KW  - glycosynthases
KW  - structure elucidation
KW  - synthetic methods
Y1  - 2018
U6  - https://doi.org/10.1002/anie.201806871
SN  - 1433-7851
SN  - 1521-3773
VL  - 57
IS  - 37
SP  - 11987
EP  - 11992
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Weiz, Annika R.
A1  - Ishida, Keishi
A1  - Quitterer, Felix
A1  - Meyer, Sabine
A1  - Kehr, Jan-Christoph
A1  - Mueller, Kristian M.
A1  - Groll, Michael
A1  - Hertweck, Christian
A1  - Dittmann-Thünemann, Elke
T1  - Harnessing the evolvability of tricyclic microviridins to dissect protease-inhibitor interactions
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Understanding and controlling proteolysis is an important goal in therapeutic chemistry. Among the natural products specifically inhibiting proteases microviridins are particularly noteworthy. Microviridins are ribosomally produced and posttranslationally modified peptides that are processed into a unique, cagelike architecture. Here, we report a combined rational and random mutagenesis approach that provides fundamental insights into selectivity-conferring moieties of microviridins. The potent variant microviridin J was co-crystallized with trypsin, and for the first time the three-dimensional structure of microviridins was determined and the mode of inhibition revealed.
KW  - cyanobacteria
KW  - peptide engineering
KW  - protease inhibitors
KW  - RiPPs
KW  - structure elucidation
Y1  - 2014
U6  - https://doi.org/10.1002/anie.201309721
SN  - 1433-7851
SN  - 1521-3773
VL  - 53
IS  - 14
SP  - 3735
EP  - 3738
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Sperlich, Eric
A1  - Köckerling, Martin
T1  - Cluster salts [Nb6Cl12(HIm)(6)]A(n) (with HIm=1H-imidazole and A=Mineral Acid Anion, n=1 or 2) made in and with Bronsted-basic ionic liquids and liquid mixtures
JF  - ChemistryOpen
N2  - Four new hexanuclear niobium cluster compounds of the general formula [Nb6Cl12(HIm)(6)](A)(n) . x(solvent molecule) (HIm=1H-imidazole, A=mineral acid anion, Cl- (n=2) (1), (SO4)(2-) (n=1) (2), (CrO4)(2-) (n=1) (3), and (HAsO4)(2-) (n=1) (4)) were prepared. Their synthesis can be done in basic ionic liquids, which form on the addition of a mineral acid, which also delivers the counter anion for the final cluster compound, to an excess of the 1H-imidazole. Some addition of an auxiliary solvent, like methanol, improves the speed of crystallisation. The cluster unit comprises a hexanuclear Nb-6 unit of octahedral shape with the edges bridged by Cl atoms and the exo sites being occupied by N-bonded 1H-imidazole ligands. The cluster cation carries sixteen cluster-based electrons. Between the NH groups of the ligands of the cluster unit, the anions and the co-crystallised water (1), or 1H-imidazole and methanol molecules (2, 3, and 4) a network of hydrogen bonds exists.
KW  - cluster
KW  - ionic liquid
KW  - structure elucidation
KW  - heterocyclic ligand
KW  - Niobium
Y1  - 2021
U6  - https://doi.org/10.1002/open.202000266
SN  - 2191-1363
VL  - 10
IS  - 2
SP  - 248
EP  - 254
PB  - Wiley-VCH
CY  - Weinheim
ER  -