Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
February 14, 2013
ChemBioChem 3/2013 Best of both worlds
Issue 3 begins with a Minireview by Florian Hollfelder (University of Cambridge) on the flexibility and reactivity in promiscuous enzymes. The efficient turnover of a range of substrates by the same enzyme is a curious feature of evolution that might afford host organisms an advantage under selective pressures. The effects of structure and reactivity upon catalytic mechanism are examined here.
Žáček et al. incubated labial glands of males from two bumblebee species (Bombus terrestris and Bombus lucorum) in vitro with radioactive [1,2-14C]acetate and deuterated [D3]acetate to investigate the biosynthesis of sexual pheromones. They found that the labeled substrates are incorporated into various compounds including terpenic alcohols and fatty acids, showing that aliphatic and terpenic pheromone components are synthesized de novo in the labial gland. In their full paper, the authors compare the qPCR analysis of fatty acid synthase transcription levels in fat bodies and labial glands. The results show that the biosynthetic activity is higher for labial gland and a function of the age of B. terrestris males.
Bacteria have developed various strategies for uptake of iron, which is an essential element but poorly bioavailable. Isabelle Schalk highlights a recent study by Raymond et al., who described for the first time a ferricitrate uptake pathway in the Gram-positive bacterium Bacillus cereus. The cytoplasmic membrane of B. cereus carries a siderophore-binding protein, FctC, and an ABC transporter, FctAB. Together, these proteins enable B. cereus to bind both Fe2Cit2 and Fe3Cit3, making it better able to compete for these essential nutrients.
This issue also contains, among others, notable contributions from Hidde Ploegh (MIT), Herbert Waldmann (Max Planck Institute of Molecular Physiology), and David Sherman (University of Michigan) and Shengying Li (Qingdao Institute of Bioenergy and Bioprocesses). Browse Issue 3/2013 now.
Recently Published Articles
- Theoretical Spectroscopy of the NiII Intermediate States in the Catalytic Cycle and the Activation of [NiFe] Hydrogenases
Dr. Tobias Krämer, Dr. Mario Kampa, Prof. Dr. Dr. Wolfgang Lubitz, Dr. Maurice van Gastel and Prof. Dr. Frank Neese
Article first published online: 22 MAY 2013 | DOI: 10.1002/cbic.201300104
Building bridges: Candidates for the Ni-SIr, Ni-SIa, and Ni-R states have been identified. The Ni-SIr and Ni-SIa states feature a water molecule loosely bound to nickel and a formally vacant bridge. For reduced Ni-R two models emerged: H2 coordinates side-on to nickel, or a hydride bridge and a protonated thiolate.
- Fluorescent Probes for Live Cell Imaging of Endogenous Guanine Nitration
Dr. Yohei Saito, Chiaki Ito, Dr. Shigemoto Fujii, Prof. Dr. Tomohiro Sawa, Prof. Dr. Takaaki Akaike and Prof. Dr. Hirokazu Arimoto
Article first published online: 22 MAY 2013 | DOI: 10.1002/cbic.201300129
Seeing is believing: S-guanylation is a novel key mechanism by which signal transduction under oxidative stress is regulated. A chemical probe whose fluorescent intensity increases after the reaction with proteinous cysteine (S-guanylation) is described. The use of this probe revealed that S-guanylation products localized in lysosomes.
- Cloning and Heterologous Expression of the Aurachin RE Biosynthesis Gene Cluster Afford a New Cytochrome P450 for Quinoline N-Hydroxylation
Dr. Wataru Kitagawa, Dr. Taro Ozaki, Dr. Taiki Nishioka, Dr. Yoshiaki Yasutake, Miyako Hata, Prof. Dr. Makoto Nishiyama, Prof. Dr. Tomohisa Kuzuyama and Prof. Dr. Tomohiro Tamura
Article first published online: 15 MAY 2013 | DOI: 10.1002/cbic.201300167
P450 makes it active: Aurachin RE is a quinoline antibiotic isolated from Rhodococcus erythropolis JCM 6824. The biosynthesis gene cluster (rau) was cloned and characterized. The P450 RauA catalyzes N-hydroxylation of the quinoline ring, thus endowing the compound with antibiotic activity.
- Metabolic Glycan Imaging by Isonitrile–Tetrazine Click Chemistry
Shaun Stairs, Dr. André A. Neves, Dr. Henning Stöckmann, Yelena A. Wainman, Dr. Heather Ireland-Zecchini, Prof. Kevin M. Brindle and Dr. Finian J. Leeper
Article first published online: 13 MAY 2013 | DOI: 10.1002/cbic.201300130
Seeing the sugar coating: N-Acetyl-glucosamine and mannosamine derivatives tagged with an isonitrile group are metabolically incorporated into cell-surface glycans and can be detected with a fluorescent tetrazine. This bioorthogonal isonitrile–tetrazine ligation is also orthogonal to the commonly used azide-cyclooctyne ligation, and so will allow simultaneous detection of the incorporation of two different sugars.
- Pulse Radiolysis Studies on the Reaction of the Reduced Vitamin B12 Complex Cob(II)alamin with Superoxide
Rohan S. Dassanayake, Dr. Diane E. Cabelli and Dr. Nicola E. Brasch
Article first published online: 13 MAY 2013 | DOI: 10.1002/cbic.201300229
O2.−scavenger: The rate constant for the rapid reaction of the ROS superoxide with the reduced vitamin B12 radical complex cob(II)alamin was directly determined to be 3.8×108 M−1 s−1. This rate was independent of pH over the range 5.5–8.7. These results have implications for studying the use of B12 supplements to combat diseases associated with oxidative stress.