14.05.2013 | Maxim B. Prigozhin; Yanxin Liu; Anna Jean Wirth; Shobhna Kapoor; Roland Winter; Klaus Schulten; Martin Gruebele, Proceedings of the National Academy of Sciences current issue, 2013

Using a newly developed microsecond pressure-jump apparatus, we monitor the refolding kinetics of the helix-stabilized five-helix bundle protein λ*YA, the Y22W/Q33Y/G46,48A mutant of λ-repressor fragment 6–85, from 3 μs to 5 ms after a 1,200-bar P-drop. In addition to a microsecond phase, we ...

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14.05.2013 | Yi Jia; Joanne Domenico; Katsuyuki Takeda; Junyan Han; Meiqin Wang; Michael Armstrong; Nichole Reisdorph; Brian P. O ..., Proceedings of the National Academy of Sciences current issue, 2013

Allergic asthma is a heterogeneous inflammatory disorder of the airways characterized by chronic airway inflammation and airway hyperresponsiveness. Numbers of CD8+IL-13+ T cells are increased in asthmatics and during the development of experimental asthma in mice. In an atopic environment ...

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14.05.2013 | Nicole M. Broekema; Michael J. Imperiale, Proceedings of the National Academy of Sciences current issue, 2013

Viral microRNAs (miRNAs) play an important role during infection by posttranscriptionally regulating both host and viral gene expression. However, the function of many viral miRNAs remains poorly understood. In this study, we investigated the role of the BK polyomavirus (BKPyV) miRNA in ...

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14.05.2013 | Erle C. Ellis; Jed O. Kaplan; Dorian Q. Fuller; Steve Vavrus; Kees Klein Goldewijk; Peter H. Verburg, Proceedings of the National Academy of Sciences current issue, 2013

Human use of land has transformed ecosystem pattern and process across most of the terrestrial biosphere, a global change often described as historically recent and potentially catastrophic for both humanity and the biosphere. Interdisciplinary paleoecological, archaeological, and historical ...

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14.05.2013 | Andrew M. Wikenheiser; David W. Stephens; A. David Redish, Proceedings of the National Academy of Sciences current issue, 2013

Laboratory studies of decision making often take the form of two-alternative, forced-choice paradigms. In natural settings, however, many decision problems arise as stay/go choices. We designed a foraging task to test intertemporal decision making in rats via stay/go decisions. Subjects did ...

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14.05.2013 | Christine S. Lane; Ben T. Chorn; Thomas C. Johnson, Proceedings of the National Academy of Sciences current issue, 2013

The most explosive volcanic event of the Quaternary was the eruption of Mt. Toba, Sumatra, 75,000 y ago, which produced voluminous ash deposits found across much of the Indian Ocean, Indian Peninsula, and South China Sea. A major climatic downturn observed within the Greenland ice cores has ...

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14.05.2013 | Andreas Vlachos; Benno Ikenberg; Maximilian Lenz; Denise Becker; Kurt Reifenberg; Carlos Bas-Orth; Thomas Deller, Proceedings of the National Academy of Sciences current issue, 2013

Synaptopodin (SP) is a marker and essential component of the spine apparatus (SA), an enigmatic cellular organelle composed of stacked smooth endoplasmic reticulum that has been linked to synaptic plasticity. However, SP/SA-mediated synaptic plasticity remains incompletely understood. To ...

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14.05.2013 | Takeshi Sakaba; Natalia L. Kononenko; Jelena Bacetic; Arndt Pechstein; Jan Schmoranzer; Lijun Yao; Holger Barth; Ole ..., Proceedings of the National Academy of Sciences current issue, 2013

Sustained fast neurotransmission requires the rapid replenishment of release-ready synaptic vesicles (SVs) at presynaptic active zones. Although the machineries for exocytic fusion and for subsequent endocytic membrane retrieval have been well characterized, little is known about the ...

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14.05.2013 | Sheng-Xiong Huang; Jeremy R. Lohman; Tingting Huang; Ben Shen, Proceedings of the National Academy of Sciences current issue, 2013

4-Methylideneimidazole-5-one (MIO)-containing aminomutases catalyze the conversion of l-α-amino acids to β-amino acids with either an (R) or an (S) configuration. l-Phenylalanine and l-tyrosine are the only two natural substrates identified to date. The enediyne chromophore of the ...

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14.05.2013 | Diego Arambula; Wenge Wong; Bob A. Medhekar; Huatao Guo; Mari Gingery; Elizabeth Czornyj; Minghsun Liu; Sanghamitra ..., Proceedings of the National Academy of Sciences current issue, 2013

Diversity-generating retroelements (DGRs) are a unique family of retroelements that confer selective advantages to their hosts by facilitating localized DNA sequence evolution through a specialized error-prone reverse transcription process. We characterized a DGR in Legionella pneumophila, an ...

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