Reverse labeling

First, note that there is a parallel relationship between high-spin tetrahedral and spin-paired planar d, as compared with the octahedral and planar situations just described. Analogous to Fig. 7-4, we have Fig. 7-5. Do not be confused about the reversed labelling of the xy and orbitals at the extremes of Fig. 7-4 and... 

The 140-residue protein AS is able to form amyloid fibrils and as such is the main component of protein inclusions involved in Parkinson s disease. Full-length 13C/15N-labelled AS fibrils and AS reverse-labelled for two of the most abundant amino acids, K and V, were examined by homonuclear and heteronuclear 2D and 3D NMR.147 Two different types of fibrils display chemical shift differences of up to 13 ppm in the l5N dimension and up to 5 ppm for the backbone and side-chain 13C chemical shifts. Selection of regions with different mobility indicates the existence of monomers in the sample and allows the identification of mobile segments of the protein within the fibril in the presence of monomeric protein. At least 35 C-terminal residues are mobile and lack a defined secondary structure, whereas the N terminus is rigid starting from residue 22. In addition, temperature-dependent sensitivity enhancement is also noted for the AS fibrils due to both the CP efficiency and motional interference with proton decoupling.148... 

Molecular properties of the H2 receptor have remained largely unknown for a long time. For instance reversible labelling of the H2 receptor was achieved only recently using [3H]tiotidine or, more reliably, [125l]iodoaminopotentidine [13],... 

Fig. 2.6 Assignment of the Met carbonyl signals of the SSI-subtilisin BPN complex by reverse double labeling methods. A) [M]SSI-subtilisin BPN complex B) [M, revl4N-V]SSI-subtiIisin BPN complex C) [M, rev14N-C]SSI-subtilisin BPN complex. (0.7 mM, 40°C, 50 mM phosphate D2O buffer pD=7.3,75.4 MHz). The result of the assignment of Met residues of [M]SSI-subtilisin BPN complex by this reverse labeling method was indicated on the spectrum (A).

Toyo oka T, Mantani T, Kato M. Reversible labeling of tyrosine residue in peptide using 4-fluoro-7-nitro-2,l,3-benzoxadiazole 131. and N-acetyl-L-cysteine. Analyt. Sci. 2003 19 341-346. 

Fluorescent styryl dyes such as FMl-43 have been used to approximate neurotransmitter release by measuring rates of ex-ocytosis (16, 72, 73). These dyes reversibly label endosomal membranes and can be taken up into intracellular synaptic vesicles during endocytosis in systems in which vesicle recycling takes place. Typically, tissue is incubated in the fluorescent dye and then stimulated to promote vesicle cycling and therefore uptake of the dye. The preparation then is washed in fresh buffer to remove dye that remained extracellular. Using fluorescent microscopy, vesicle dynamics can be tracked. Neurotransmitter release is estimated from the rate of destaining (because of exocytosis) usually during stimulation. 

Although both nuclear spin dependent neutron scattering and resonant X-ray scattering are non-destructive, reversible, labelling techniques, their use in macromolecular structure research is complementary. 

Each sample is reverse labeled on two replicates, and all samples are randomly paired with every other sample. Sample 1 is in boldface to demonstrate this design. 

Gevaert, K. Ghesquiere, B. Staes, A. Martens, L. Van Damme, J. Thomas, G.R. Vandekerckhove, J. Reversible labeling of cysteine-containing peptides allows their specific chromatographic isolation for non-gel proteome studies. Proteomics 2004, 4, 897-908. 

Fig. 11.14 Tetrahenzoxazines (/f)-3 and (S)-3 and tetrakis-aminomethylated Fesoicinarene (S)-17. Quaternary ammonium ions (18). Isotope pattern regions of the ESI-PTlCR (FTICR Fourier transform ion cyclotron resonance) mass spectra of (S)-17 with pseudo-racemates of the two guests. The bottom row represents control experiments with a reversed labelling of the two guest enantiomers as compared to the top row [35] (Image reproduced frinn [35] with permission from Springer)...

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