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
- 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.
- Decoupled Roles for the Atypical, Bifurcated Binding Pocket of the ybfF Hydrolase
Elizabeth E. Ellis, Dr. Chinessa T. Adkins, Natalie M. Galovska, Dr. Luke D. Lavis and Dr. R. Jeremy Johnson
Article first published online: 13 MAY 2013 | DOI: 10.1002/cbic.201300085
A fork in the pocket: The bifurcated lobes of the substrate-binding pocket of the ybfF hydrolase from Vibrio cholerae provide distinct contributions to its overall activity and stability. The distinct roles of the two lobes allow the thermal stability and substrate selectivity of ybfF to be decoupled for biocatalyst design.
- A Tandem Chemoenzymatic Methylation by S-Adenosyl-L-methionine (pages 950–953)
Joseph M. Lipson, Marie Thomsen, Prof. Bradley S. Moore, Dr. Rasmus P. Clausen, Dr. James J. La Clair and Prof. Michael D. Burkart
Article first published online: 6 MAY 2013 | DOI: 10.1002/cbic.201300221
Keep ′em methylated: The in situ preparation of the cofactor AdoMet was achieved by allowing the biosynthetic enzyme SalL to operate in the reverse direction by presentation of 5′-chloro-5′-deoxyadenosine at low salt concentrations. This reaction was readily coupled with DNA and small molecule methyltransferases to afford a regioselective method for chemo-enzymatic methylation and isotope incorporation.