23.08.2011 | Han, H., Hemp, J., Pace, L. A., Ouyang, H., Ganesan, K., Roh, J. H., Daldal, F., Blanke, S. R., Gennis, R. B., Proceedings of the National Academy of Sciences current issue, 2011

Aerobic respiration in bacteria, Archaea, and mitochondria is performed by oxygen reductase members of the heme-copper oxidoreductase superfamily. These enzymes are redox-driven proton pumps which conserve part of the free energy released from oxygen reduction to generate a proton motive ...

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23.08.2011 | Kang, H. C., Lee, Y.–I., Shin, J.–H., Andrabi, S. A., Chi, Z., Gagne, J.–P., Lee, Y., Ko, H. S., L ..., Proceedings of the National Academy of Sciences current issue, 2011

Ubiquitin mediated protein degradation is crucial for regulation of cell signaling and protein quality control. Poly(ADP-ribose) (PAR) is a cell-signaling molecule that mediates changes in protein function through binding at PAR binding sites. Here we characterize the PAR binding protein, ...

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23.08.2011 | Fang, P.-A., Conway, J. F., Margolis, H. C., Simmer, J. P., Beniash, E., Proceedings of the National Academy of Sciences current issue, 2011

Enamel is a highly organized hierarchical nanocomposite, which consists of parallel arrays of elongated apatitic crystallites forming an intricate three-dimensional microstructure. Amelogenin, the major extracellular matrix protein of dental enamel, regulates the formation of these ...

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23.08.2011 | Rocha, Rita; Pereira, Pedro José Barbosa; Santos, Manuel A. S.; Macedo-Ribeiro, Sandra, Proceedings of the National Academy of Sciences current issue, 2011

In a restricted group of opportunistic fungal pathogens the universal leucine CUG codon is translated both as serine (97%) and leucine (3%), challenging the concept that translational ambiguity has a negative impact in living organisms. To elucidate the molecular mechanisms underlying the in ...

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23.08.2011 | Gubaev, A., Klostermeier, D., Proceedings of the National Academy of Sciences current issue, 2011

DNA gyrase introduces negative supercoils into DNA in an ATP-dependent reaction. DNA supercoiling is catalyzed by a strand-passage mechanism, in which a T-segment of DNA is passed through the gap in a transiently cleaved G-segment. Strand passage requires the coordinated closing and opening ...

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23.08.2011 | Keeffe, J. R., Gnanapragasam, P. N. P., Gillespie, S. K., Yong, J., Bjorkman, P. J., Mayo, S. L., Proceedings of the National Academy of Sciences current issue, 2011

Cyanovirin-N (CV-N) is a small, cyanobacterial lectin that neutralizes many enveloped viruses, including human immunodeficiency virus type I (HIV-1). This antiviral activity is attributed to two homologous carbohydrate binding sites that specifically bind high mannose glycosylation present on ...

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23.08.2011 | Halime, Z., Kotani, H., Li, Y., Fukuzumi, S., Karlin, K. D., Proceedings of the National Academy of Sciences current issue, 2011

An efficient and selective four-electron plus four-proton (4e-/4H+) reduction of O2 to water by decamethylferrocene and trifluoroacetic acid can be catalyzed by a synthetic analog of the heme a3/CuB site in cytochrome c oxidase (6LFeCu) or its Cu-free version (6LFe) in acetone. A detailed ...

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23.08.2011 | Kamat, N. P., Liao, Z., Moses, L. E., Rawson, J., Therien, M. J., Dmochowski, I. J., Hammer, D. A., Proceedings of the National Academy of Sciences current issue, 2011

Probes embedded within a structure can enable prediction of material behavior or failure. Carefully assembled composites that respond intelligently to physical changes within a material could be useful as intrinsic sensors. Molecular rotors are one such tool that can respond optically to ...

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23.08.2011 | Cardamone, Luca; Laio, Alessandro; Torre, Vincent; Shahapure, Rajesh; DeSimone, Antonio, Proceedings of the National Academy of Sciences current issue, 2011

Growing networks of actin fibers are able to organize into compact, stiff two-dimensional structures inside lamellipodia of crawling cells. We put forward the hypothesis that the growing actin network is a critically self-organized system, in which long-range mechanical stresses arising from ...

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23.08.2011 | Jung, W., Cho, D., Kim, M.-K., Choi, H. J., Lyo, I.-W., Proceedings of the National Academy of Sciences current issue, 2011

The capability to deposit charge and energy quantum-by-quantum into a specific atomic site could lead to many previously unidentified applications. Here we report on the quantum capacitor formed by a strongly localized field possessing such capability. We investigated the charging dynamics of ...

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