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Prinz H.,Max Planck Institute For Molekulare Physiologie
Journal of Chemical Biology | Year: 2010

Hill coefficients (n H) derived from four parameter logistic fits to dose-response curves were compared to calculated realistic reaction schemes and related to experimental data: (1) Hill coefficients may give information on the number of interacting sites but cannot distinguish between competitive, non-competitive or ortho-, iso-, or allosteric mechanisms. (2) For enzymatic dose-inhibition curves, Hill coefficients smaller than one do not indicate anticooperative binding but show that at least one ternary complex has enzymatic activity. (3) Hill coefficients different from one are proof for multiple ligand binding. The large variations of reported Hill coefficients corresponds to multiple allosteric binding, where induced conformational changes cause loss of the active conformation. Such a denaturation mechanism is in stark contrast to the desired specificity of drugs. The discussion is open. © 2009 Springer-Verlag. Source

Seebeck F.P.,Max Planck Institute For Molekulare Physiologie
Journal of the American Chemical Society | Year: 2010

Ergothioneine is a histidine-derived thiol of bacterial and fungal origin that has also been isolated from animal and human tissue. Recent findings point to critical functions of ergothioneine in human physiology, but its role in microbial life is poorly understood. This report describes the identification of the ergothioneine biosynthetic gene cluster from mycobacteria and in vitro reconstitution of this process using recombinant proteins from Mycobacterium smegmatis. The key reactions are catalyzed by a methyltransferase that transfers three methyl groups to the α-amino moiety of histidine and an iron(II)-dependent enzyme that catalyzes oxidative sulfurization of trimethylhistidine. A search for homologous genes indicated that ergothioneine production is a frequent trait among fungi, actinobacteria, and cyanobacteria but also occurs in numerous bacteroidetes and proteobacteria. © 2010 American Chemical Society. Source

Samanta R.,Max Planck Institute For Molekulare Physiologie | Antonchick A.P.,Max Planck Institute For Molekulare Physiologie
Angewandte Chemie - International Edition | Year: 2011

S=O shows where to go: A novel double C-H activation of aromatic compounds with a sulfoxide as a directing group results in the highly regioselective synthesis of polysubstituted dibenzothiophenes (see scheme). The reaction cascade consists of palladium-catalyzed double C-H activation and a Pummerer rearrangement followed by palladium-catalyzed C-S bond formation. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Schonichen A.,Max Planck Institute For Molekulare Physiologie | Geyer M.,Max Planck Institute For Molekulare Physiologie
Biochimica et Biophysica Acta - Molecular Cell Research | Year: 2010

The regulation of the actin cytoskeleton is a key process for the stability and motility of eukaryotic cells. Besides the Arp2/3 complex and its nucleation promoting factors, WH2 domain-containing proteins and a diverse family of formin proteins have recently been recognized as actin nucleators and potent polymerization factors of actin filaments. Formins are defined by the presence of a catalytic formin homology 2 (FH2) domain, yet, the modular domain architecture appears significantly different for the eight formin families identified in humans. A diverse picture of protein localization, interaction partners and cell specific regulation emerged, suggesting various functions of formins in the building and maintenance of actin filaments. This review focuses on the domain architecture of human formins, the regulation mechanisms of their activation and the diversity in formin cellular functions. © 2010 Elsevier B.V. All rights reserved. Source

Matcha K.,Max Planck Institute For Molekulare Physiologie | Antonchick A.P.,Max Planck Institute For Molekulare Physiologie
Angewandte Chemie - International Edition | Year: 2013

A range of heterocyclic compounds were synthesized by a novel, metal-free cross-dehydrogenative coupling between heterocycles and aldehydes under mild reaction conditions that are not sensitive to moisture. The products are formed smoothly and regioselectively at room temperature by a hypervalent iodine mediated transformation. This method has a broad substrate scope and was used in the highly efficient, one-step synthesis of natural products. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

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