TY  - JOUR
A1  - Hagen, Sven
A1  - Baumann, Tobias
A1  - Wagner, Hanna J.
A1  - Morath, Volker
A1  - Kaufmann, Beate
A1  - Fischer, Adrian
A1  - Bergmann, Stefan
A1  - Schindler, Patrick
A1  - Arndt, Katja Maren
A1  - Mueller, Kristian M.
T1  - Modular adeno-associated virus (rAAV) vectors used for cellular virus-directed enzyme prodrug therapy
JF  - Scientific reports
N2  - The pre-clinical and clinical development of viral vehicles for gene transfer increased in recent years, and a recombinant adeno-associated virus (rAAV) drug took center stage upon approval in the European Union. However, lack of standardization, inefficient purification methods and complicated retargeting limit general usability. We address these obstacles by fusing rAAV-2 capsids with two modular targeting molecules (DARPin or Affibody) specific for a cancer cell-surface marker (EGFR) while simultaneously including an affinity tag (His-tag) in a surface-exposed loop. Equipping these particles with genes coding for prodrug converting enzymes (thymidine kinase or cytosine deaminase) we demonstrate tumor marker specific transduction and prodrug-dependent apoptosis of cancer cells. Coding terminal and loop modifications in one gene enabled specific and scalable purification. Our genetic parts for viral production adhere to a standardized cloning strategy facilitating rapid prototyping of virus directed enzyme prodrug therapy (VDEPT).
Y1  - 2014
U6  - https://doi.org/10.1038/srep03759
SN  - 2045-2322
VL  - 4
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Hagen, Sven
A1  - Mattay, Dinah
A1  - Raeuber, Christina
A1  - Mueller, Kristian M.
A1  - Arndt, Katja Maren
T1  - Characterization and inhibition of AF10-mediated interaction
JF  - Journal of peptide science
N2  - The non-random chromosomal translocations t(10;11)(p13;q23) and t(10;11)(p13;q14-21) result in leukemogenic fusion proteins comprising the coiled coil domain of the transcription factor AF10 and the proteins MLL or CALM, respectively, and subsequently cause certain types of acute leukemia. The AF10 coiled-coil domain, which is crucial for the leukemogenic effect, has been shown to interact with GAS41, a protein previously identified as the product of an amplified gene in glioblastoma. Using sequential synthetic peptides, we mapped the potential AF10/GAS41 interaction site, which was subsequently be used as scaffold for a library targeting the AF10 coiled-coil domain. Using phage display, we selected a peptide that binds the AF10 coiled-coil domain with higher affinity than the respective coiled-coil region of wild-type GAS41, as demonstrated by phage ELISA, CD, and PCAs. Furthermore, we were able to successfully deploy the inhibitory peptide in a mammalian cell line to lower the expression of Hoxa genes that have been described to be overexpressed in these leukemias. This work dissects molecular determinants mediating AF10-directed interactions in leukemic fusions comprising the N-terminal parts of the proteins MLL or CALM and the C-terminal coiled-coil domain of AF10. Furthermore, it outlines the first steps in recognizing and blocking the leukemia-associated AF10 interaction in histiocytic lymphoma cells and therefore, may have significant implications in future diagnostics and therapeutics. Copyright (c) 2014 European Peptide Society and John Wiley & Sons, Ltd.
KW  - protein-protein interaction
KW  - protein design and selection
KW  - protein engineering
KW  - coiled coil
KW  - leucine zipper
KW  - AF10
Y1  - 2014
U6  - https://doi.org/10.1002/psc.2626
SN  - 1075-2617
SN  - 1099-1387
VL  - 20
IS  - 6
SP  - 385
EP  - 397
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Kuekenshoener, Tim
A1  - Wohlwend, Daniel
A1  - Niemoeller, Christoph
A1  - Dondapati, Padmarupa
A1  - Speck, Janina
A1  - Adeniran, Adebola V.
A1  - Nieth, Anita
A1  - Gerhardt, Stefan
A1  - Einsle, Oliver
A1  - Mueller, Kristian M.
A1  - Arndt, Katja Maren
T1  - Improving coiled coil stability while maintaining specificity by a bacterial hitchhiker selection system
JF  - Journal of structural biology
N2  - The design and selection of peptides targeting cellular proteins is challenging and often yields candidates with undesired properties. Therefore we deployed a new selection system based on the twin-arginine translocase (TAT) pathway of Escherichia coli, named hitchhiker translocation (HiT) selection. A pool of alpha-helix encoding sequences was designed and selected for interference with the coiled coil domain (CC) of a melanoma-associated basic-helix-loop-helix-leucine-zipper (bHLHLZ) protein, the microphthalmia associated transcription factor (MITF). One predominant sequence (iM10) was enriched during selection and showed remarkable protease resistance, high solubility and thermal stability while maintaining its specificity. Furthermore, it exhibited nanomolar range affinity towards the target peptide. A mutation screen indicated that target-binding helices of increased homodimer stability and improved expression rates were preferred in the selection process. The crystal structure of the iM10/MITF-CC heterodimer (2.1 angstrom) provided important structural insights and validated our design predictions. Importantly, iM10 did not only bind to the MITF coiled coil, but also to the markedly more stable HLHLZ domain of MITF. Characterizing the selected variants of the semi-rational library demonstrated the potential of the innovative bacterial selection approach. (C) 2014 Elsevier Inc. All rights reserved.
KW  - Basic helix-loop-helix leucine zipper
KW  - Coiled coils
KW  - Microphthalmia associated transcription factor
KW  - Selection and design
KW  - Twin arginine translocation pathway
Y1  - 2014
U6  - https://doi.org/10.1016/j.jsb.2014.03.002
SN  - 1047-8477
SN  - 1095-8657
VL  - 186
IS  - 3
SP  - 335
EP  - 348
PB  - Elsevier
CY  - San Diego
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  - Kuekenshoener, Tim
A1  - Hagemann, Urs B.
A1  - Wohlwend, Daniel
A1  - Raeuber, Christina
A1  - Baumann, Tobias
A1  - Keller, Sandro
A1  - Einsle, Oliver
A1  - Mueller, Kristian M.
A1  - Arndt, Katja Maren
T1  - Analysis of Selected and Designed Chimeric D- and L-alpha-Helix Assemblies
JF  - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences
N2  - D-Peptides have been attributed pharmacological advantages over regular L-peptides, yet design rules are largely unknown. Based on a designed coiled coil-like D/L heterotetramer, named L-Base/D-Acid, we generated a library offering alternative residues for interaction with the D-peptide. Phage display selection yielded one predominant peptide, named HelixA, that differed at 13 positions from the scaffold helix. In addition to the observed D-/L-heterotetramers, ratio-dependent intermediate states were detected by isothermal titration calorimetry. Importantly, the formation of the selected HelixA/D-Acid bundle passes through fewer intermediate states than L-Base/D-Acid. Back mutation of HelixA core residues to L-Base (HelixLL) revealed that the residues at e/g-positions are responsible for the different intermediates. Furthermore, a Val-core variant (PeptideVV) was completely devoid of binding D-Acid, whereas an Ile-core helix (HelixII) interacted with D-Acid in a significantly more specific complex than L-Base.
Y1  - 2014
U6  - https://doi.org/10.1021/bm5006883
SN  - 1525-7797
SN  - 1526-4602
VL  - 15
IS  - 9
SP  - 3296
EP  - 3305
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Hoffmann, Stefan A.
A1  - Wohltat, Christian
A1  - Mueller, Kristian M.
A1  - Arndt, Katja Maren
T1  - A user-friendly, low-cost turbidostat with versatile growth rate estimation based on an extended Kalman filter
JF  - PLoS one
N2  - For various experimental applications, microbial cultures at defined, constant densities are highly advantageous over simple batch cultures. Due to high costs, however, devices for continuous culture at freely defined densities still experience limited use. We have developed a small-scale turbidostat for research purposes, which is manufactured from inexpensive components and 3D printed parts. A high degree of spatial system integration and a graphical user interface provide user-friendly operability. The used optical density feedback control allows for constant continuous culture at a wide range of densities and offers to vary culture volume and dilution rates without additional parametrization. Further, a recursive algorithm for on-line growth rate estimation has been implemented. The employed Kalman filtering approach based on a very general state model retains the flexibility of the used control type and can be easily adapted to other bioreactor designs. Within several minutes it can converge to robust, accurate growth rate estimates. This is particularly useful for directed evolution experiments or studies on metabolic challenges, as it allows direct monitoring of the population fitness.
Y1  - 2017
U6  - https://doi.org/10.1371/journal.pone.0181923
SN  - 1932-6203
VL  - 12
SP  - 5944
EP  - 5952
PB  - PLoS
CY  - San Fransisco
ER  -