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911.
Structural Insights into the Incorporation of the Mo Cofactor into Sulfite Oxidase from Site‐Directed Spin Labeling
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Dr. Aaron Hahn Christopher Engelhard Dr. Stefan Reschke Dr. Christian Teutloff Prof. Dr. Robert Bittl Prof. Dr. Silke Leimkühler Prof. Dr. Thomas Risse 《Angewandte Chemie (International ed. in English)》2015,54(40):11865-11869
Mononuclear molybdoenzymes catalyze a broad range of redox reactions and are highly conserved in all kingdoms of life. This study addresses the question of how the Mo cofactor (Moco) is incorporated into the apo form of human sulfite oxidase (hSO) by using site‐directed spin labeling to determine intramolecular distances in the nanometer range. Comparative measurements of the holo and apo forms of hSO enabled the localization of the corresponding structural changes, which are localized to a short loop (residues 263–273) of the Moco‐containing domain. A flap‐like movement of the loop provides access to the Moco binding‐pocket in the apo form of the protein and explains the earlier studies on the in vitro reconstitution of apo‐hSO with Moco. Remarkably, the loop motif can be found in a variety of structurally similar molybdoenzymes among various organisms, thus suggesting a common mechanism of Moco incorporation. 相似文献
912.
Nishit Goradia Christoph Wiedemann Dr. Christian Herbst Dr. Matthias Görlach Prof. Dr. Stefan H. Heinemann Dr. Oliver Ohlenschläger Dr. Ramadurai Ramachandran 《Chemphyschem》2015,16(4):739-746
An efficient approach to NMR assignments in intrinsically disordered proteins is presented, making use of the good dispersion of cross peaks observed in [15N,13C′]‐ and [13C′,1HN]‐correlation spectra. The method involves the simultaneous collection of {3D (H)NCO(CAN)H and 3D (HACA)CON(CA)HA} spectra for backbone assignments via sequential HN and Hα correlations and {3D (H)NCO(CACS)HS and 3D (HS)CS(CA)CO(N)H} spectra for side‐chain 1H and 13C assignments, employing sequential 1H data acquisitions with direct detection of both the amide and aliphatic protons. The efficacy of the approach for obtaining resonance assignments with complete backbone and side‐chain chemical shifts is demonstrated experimentally for the 61‐residue [13C,15N]‐labelled peptide of a voltage‐gated potassium channel protein of the Kv1.4 channel subunit. The general applicability of the approach for the characterisation of moderately sized globular proteins is also demonstrated. 相似文献
913.
Susana Chatzipapadopoulos Tobias Zentel Prof. Dr. Ralf Ludwig Matthias Lütgens Prof. Dr. Stefan Lochbrunner Prof. Dr. Oliver Kühn 《Chemphyschem》2015,16(12):2519-2523
Understanding both structure and dynamics is crucial for producing tailor‐made ionic liquids (ILs). We studied the vibrational and structural dynamics of medium versus weakly hydrogen‐bonded C?H groups of the imidazolium ring in ILs of the type [1‐alkyl‐3‐methylimidazolium][bis(trifluoromethanesulfonyl)imide] ([Cnmim][NTf2]), with n=1, 2, and 8, by time‐resolved coherent anti‐Stokes Raman scattering (CARS) and quantum‐classical hybrid (QCH) simulations. From the time series of the CARS spectra, dephasing times were extracted by modeling the full nonlinear response. From the QCH calculations, pure dephasing times were obtained by analyzing the distribution of transition frequencies. Experiments and calculations reveal larger dephasing rates for the vibrational stretching modes of C(2)?H compared with the more weakly hydrogen‐bonded C(4,5)?H. This finding can be understood in terms of different H‐bonding motifs and the fast interconversion between them. Differences in population relaxation rates are attributed to Fermi resonance interactions. 相似文献
914.
Production of the Bengamide Class of Marine Natural Products in Myxobacteria: Biosynthesis and Structure–Activity Relationships
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Dr. Silke C. Wenzel Dr. Holger Hoffmann Dr. Jidong Zhang Dr. Laurent Debussche Dr. Sabine Haag‐Richter Dr. Michael Kurz Dr. Frederico Nardi Dr. Peer Lukat Irene Kochems Dr. Heiko Tietgen Prof. Dr. Dietmar Schummer Jean‐Paul Nicolas Dr. Loreley Calvet Dr. Valerie Czepczor Dr. Patricia Vrignaud Dr. Agnes Mühlenweg Priv.‐Doz. Dr. Stefan Pelzer Prof. Dr. Rolf Müller Prof. Dr. Mark Brönstrup 《Angewandte Chemie (International ed. in English)》2015,54(51):15560-15564
The bengamides, sponge‐derived natural products that have been characterized as inhibitors of methionine aminopeptidases (MetAPs), have been intensively investigated as anticancer compounds. We embarked on a multidisciplinary project to supply bengamides by fermentation of the terrestrial myxobacterium M. virescens, decipher their biosynthesis, and optimize their properties as drug leads. The characterization of the biosynthetic pathway revealed that bacterial resistance to bengamides is conferred by Leu 154 of the myxobacterial MetAP protein, and enabled transfer of the entire gene cluster into the more suitable production host M. xanthus DK1622. A combination of semisynthesis of microbially derived bengamides and total synthesis resulted in an optimized derivative that combined high cellular potency in the nanomolar range with high metabolic stability, which translated to an improved half‐life in mice and antitumor efficacy in a melanoma mouse model. 相似文献
915.
916.
917.
Dr. Guang‐Ping Hao Giovanni Mondin Dr. Zhikun Zheng Tim Biemelt Stefan Klosz René Schubel Prof. Alexander Eychmüller Prof. Stefan Kaskel 《Angewandte Chemie (International ed. in English)》2015,54(6):1941-1945
There is significant interest in high‐performance materials that can directly and efficiently capture water vapor, particularly from air. Herein, we report a class of novel porous carbon cuboids with unusual ultra‐hydrophilic properties, over which the synergistic effects between surface heterogeneity and micropore architecture is maximized, leading to the best atmospheric water‐capture performance among porous carbons to date, with a water capacity of up to 9.82 mmol g?1 at P/P0=0.2 and 25 °C (20 % relative humidity or 6000 ppm). Benefiting from properties, such as defined morphology, narrow pore size distribution, and high heterogeneity, this series of functional carbons may serve as model materials for fundamental research on carbon chemistry and the advance of new types of materials for water‐vapor capture as well as other applications requiring combined highly hydrophilic surface chemistry, developed hierarchical porosity, and excellent stability. 相似文献
918.
Dr. James R. Frost Prof. Dr. Stefan M. Huber Dr. Stefan Breitenlechner M. Sc. Christoph Bannwarth Prof. Dr. Thorsten Bach 《Angewandte Chemie (International ed. in English)》2015,54(2):691-695
Spirocyclic oxindoles undergo an enantioselective oxygenation reaction (nine examples; e.r. up to 97:3) upon catalysis by a chiral ruthenium porphyrin complex (1 mol %). The catalyst exhibits a lactam ring, which is responsible for substrate association through hydrogen bonds, and an active ruthenium center, which is in a defined spatial relationship to the oxygenation substrate. DFT calculations illustrate the perfect alignment of the active site with the reactive C? H bond and suggest—in line with the kinetic isotope effect—an oxygen rebound mechanism for the reaction. 相似文献
919.
Total Synthesis of Albicidin: A Lead Structure from Xanthomonas albilineans for Potent Antibacterial Gyrase Inhibitors
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Julian Kretz Dennis Kerwat Vivien Schubert Stefan Grätz Alexander Pesic Siamak Semsary Stéphane Cociancich Monique Royer Prof. Dr. Roderich D. Süssmuth 《Angewandte Chemie (International ed. in English)》2015,54(6):1969-1973
The peptide antibiotic albicidin, which is synthesized by the plant pathogenic bacterium Xanthomonas albilineans, displays remarkable antibacterial activity against various Gram‐positive and Gram‐negative microorganisms. The low amounts of albicidin obtainable from the producing organism or through heterologous expression are limiting factors in providing sufficient material for bioactivity profiling and structure–activity studies. Therefore, we developed a convergent total synthesis route toward albicidin. The unexpectedly difficult formation of amide bonds between the aromatic amino acids was achieved through a triphosgene‐mediated coupling strategy. The herein presented synthesis of albicidin confirms the previously determined chemical structure and underlines the extraordinary antibacterial activity of this compound. The synthetic protocol will provide multigram amounts of albicidin for further profiling of its drug properties. 相似文献
920.
Structural Characterization of O‐ and C‐Glycosylating Variants of the Landomycin Glycosyltransferase LanGT2
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Dr. Heng Keat Tam Dr. Johannes Härle Dr. Stefan Gerhardt Prof. Dr. Jürgen Rohr Guojun Wang Prof. Dr. Jon S. Thorson Dr. Aurélien Bigot Monika Lutterbeck Dr. Wolfgang Seiche Prof. Dr. Bernhard Breit Prof. Dr. Andreas Bechthold Prof. Dr. Oliver Einsle 《Angewandte Chemie (International ed. in English)》2015,54(9):2811-2815
The structures of the O‐glycosyltransferase LanGT2 and the engineered, C? C bond‐forming variant LanGT2S8Ac show how the replacement of a single loop can change the functionality of the enzyme. Crystal structures of the enzymes in complex with a nonhydrolyzable nucleotide‐sugar analogue revealed that there is a conformational transition to create the binding sites for the aglycon substrate. This induced‐fit transition was explored by molecular docking experiments with various aglycon substrates. 相似文献