TY  - JOUR
A1  - Reyna-González, Emmanuel
A1  - Schmid, Bianca
A1  - Petras, Daniel
A1  - Süssmuth, Roderich D.
A1  - Dittmann, Elke
T1  - Leader Peptide-Free In Vitro Reconstitution of Microviridin Biosynthesis Enables Design of Synthetic Protease-Targeted Libraries
JF  - Angewandte Chemie : a journal of the Gesellschaft Deutscher Chemiker ; International edition
N2  - Microviridins are a family of ribosomally synthesized and post-translationally modified peptides with a highly unusual architecture featuring non-canonical lactone as well as lactam rings. Individual variants specifically inhibit different types of serine proteases. Here we have established an efficient in vitro reconstitution approach based on two ATP-grasp ligases that were constitutively activated using covalently attached leader peptides and a GNAT-type N-acetyltransferase. The method facilitates the efficient in vitro one-pot transformation of microviridin core peptides to mature microviridins. The engineering potential of the chemo-enzymatic technology was demonstrated for two synthetic peptide libraries that were used to screen and optimize microviridin variants targeting the serine proteases trypsin and subtilisin. Successive analysis of intermediates revealed distinct structure-activity relationships for respective target proteases.
KW  - biosynthesis
KW  - cyanobacteria
KW  - microviridins
KW  - natural products
KW  - peptides
Y1  - 2016
U6  - https://doi.org/10.1002/anie.201604345
SN  - 1433-7851
SN  - 1521-3773
VL  - 55
SP  - 9398
EP  - 9401
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Wolff, Martin
A1  - Gast, Klaus
A1  - Evers, Andreas
A1  - Kurz, Michael
A1  - Pfeiffer-Marek, Stefania
A1  - Schüler, Anja
A1  - Seckler, Robert
A1  - Thalhammer, Anja
T1  - A Conserved Hydrophobic Moiety and Helix-Helix Interactions Drive the Self-Assembly of the Incretin Analog Exendin-4
JF  - Biomolecules
N2  - Exendin-4 is a pharmaceutical peptide used in the control of insulin secretion. Structural information on exendin-4 and related peptides especially on the level of quaternary structure is scarce. We present the first published association equilibria of exendin-4 directly measured by static and dynamic light scattering. We show that exendin-4 oligomerization is pH dependent and that these oligomers are of low compactness. We relate our experimental results to a structural hypothesis to describe molecular details of exendin-4 oligomers. Discussion of the validity of this hypothesis is based on NMR, circular dichroism and fluorescence spectroscopy, and light scattering data on exendin-4 and a set of exendin-4 derived peptides. The essential forces driving oligomerization of exendin-4 are helix–helix interactions and interactions of a conserved hydrophobic moiety. Our structural hypothesis suggests that key interactions of exendin-4 monomers in the experimentally supported trimer take place between a defined helical segment and a hydrophobic triangle constituted by the Phe22 residues of the three monomeric subunits. Our data rationalize that Val19 might function as an anchor in the N-terminus of the interacting helix-region and that Trp25 is partially shielded in the oligomer by C-terminal amino acids of the same monomer. Our structural hypothesis suggests that the Trp25 residues do not interact with each other, but with C-terminal Pro residues of their own monomers.
KW  - biophysics
KW  - diabetes
KW  - peptides
KW  - oligomerization
KW  - conformational change
KW  - molecular modeling
KW  - static and dynamic light scattering
KW  - spectroscopy
Y1  - 2021
U6  - https://doi.org/10.3390/biom11091305
SN  - 2218-273X
VL  - 11
IS  - 9
PB  - MDPI
CY  - Basel
ER  -