Fragments of G protein-coupled receptors (GPCRs) are widely used as models to investigate these polytopic integral-membrane, signal-transducing molecules, but have proven difficult to prepare in quantities necessary for NMR analyses. We report on the biosynthesis of two double transmembrane (TM) containing fragments of Ste2p, the alpha-factor GPCR from the yeast Saccharomyces cerevisiae. Ste2p(...

Labeling DNA with stable isotopes to measure cell proliferation can be a technique as effective as 3H-thymidine labeling without the limitations imposed by using radioisotopes. Here, we investigated the relative efficiency of four nonradioactive precursors to DNA: [1-13C]-glycine, [1,2-13C2]-glycine, [U-13C]-glucose, and [U-13C, 15N]-thymidine. The efficiency of incorporation for each of these ...

straw burned (Bird et al., 2001; 2002). Recent work in tropical and temperate rice ecosystems has determined The transition from open-field burning of straw residues to alternathat the operationally-defined mobile humic fraction tive residue management practices may affect soil C sequestration potential and the supply of nutrients to crops. A field study of dual(Na4P2O7 or NaOH extractable) is ...

Soybean/maize intercropping has remarkable advantages in increasing crop yield and nitrogen (N) efficiency. However, little is known about the contributions of rhizobia or arbuscular mycorrhizal fungi (AMF) to yield increases and N acquisition in the intercropping system. Plus, the mechanisms controlling carbon (C) and N allocation in intercropping systems remain unsettled. In the present study...

Abstract Aims Competition among plants in a community usually depends on their nitrogen (N)-use efficiency (NUE) and water-use (WUE) arid semi-arid regions. Artemisia frigida is an indicator species heavily degraded grassland, however, how its NUE WUE respond to N addition different successional stages still unclear, especially with mowing, common management practice grasslands. Methods Based l...

The three-dimensional solution structure of the 259-residue 30 kDa N-terminal domain of enzyme I (EIN) of the phosphoenolpyruvate:sugar phosphotransferase system of Escherichia coli has been determined by multidimensional nuclear magnetic resonance spectroscopy. Enzyme I, which is autophosphorylated by phosphoenolpyruvate, reversibly phosphorylates the phosphocarrier protein HPr, which in turn ...

Upon alignment of oligonucleotides in a magnetic field, the downfield TROSY component of the 13C-{1H} doublet changes its resonance frequency as a result of residual 13C-1H dipolar coupling (RDC) and residual 13C chemical shift anisotropy (RCSA), and the sum of these two second rank tensors is referred to as the pseudo-CSA. The experimentally measured difference in the resonance frequency of th...