@article {461,
	title = {Synthesis and conformational dynamics of ortho-xylyl-bridged-[4]cavitands},
	journal = {Tetrahedron},
	volume = {58},
	number = {4},
	year = {2002},
	note = {ISI Document Delivery No.: 515QLTimes Cited: 10Cited Reference Count: 24},
	month = {Jan},
	pages = {787-798},
	type = {Article},
	abstract = {ortho-Xylyl-[4]cavitands 2 to 6 were synthesized from bromoresorcin[4] arenes 1. Cavitands 2 to 6 show C-4nu symmetry in their H-1 NMR spectra at higher temperatures. Dynamic H-1 NMR studies of 2 to 6 indicate the C-4nu symmetry is due to fast interconversion of rectangular C-2nu isomers. This is supported by the crystal structure of 2a, which shows a C-2nu rectangular structure. The activation energy barriers for 2a and 2b were measured by quantitative 1D NOESY (EXSY) experiments. The results were analyzed by the initial rate approximation and matrix calculations. The activation energy barrier was found to depend strongly on the size of the upper rim group (Br, H, OH, CN). In addition, replacing the phenolic proton of tetrol derivatives 4a and 4b with metal ions raises the energy barrier further, likely via bridging metal cations. The two tetrabromo compounds (2a and 2b) reveal a sensitivity of the activation barrier to the feet of the cavitands. Cavitand 6 may act as a hub for radially expanded cavitands. The advantages of the 1D NOESY experiments over the more commonly used two-dimensional experiments are discussed. (C) 2002 Elsevier Science Ltd. All rights reserved.},
	keywords = {1D NOESY (EXSY), CARCEPLEXES, CAVITANDS, CHEMICAL-EXCHANGE, DEEP-CAVITY CAVITANDS, dynamic H-1 NMR, EXCHANGE, HEMICARCEPLEXES, KINETICS, MAGNETIC-RESONANCE SPECTROSCOPY, NMR},
	isbn = {0040-4020},
	url = {<Go to ISI>://000173506800019},
	author = {Naumann, C. and Patrick, B. O. and Sherman, J. C.}
}
@article {4578,
	title = {The cellulose-binding domains from Cellulomonas fimi beta-1,4-glucanase CenC bind nitroxide spin-labeled cellooligosaccharides in multiple orientations},
	journal = {Journal of Molecular Biology},
	volume = {287},
	number = {3},
	year = {1999},
	note = {ISI Document Delivery No.: 184RGTimes Cited: 38Cited Reference Count: 46},
	month = {Apr},
	pages = {609-625},
	type = {Article},
	abstract = {The N-terminal cellulose-binding domains CBDN1 and CBDN2 from Cellulomonas fimi cellulase CenC each adopt a jelly-roll beta-sandwich structure with a cleft into which amorphous cellulose and soluble cellooligosaccharides bind. To determine the orientation of the sugar chain within these binding clefts, the association of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl-4-yl) spin-labeled derivatives of cellotriose and cellotetraose with isolated CBDN1 and CBDN2 was studied using heteronuclear H-1-N-15 NMR spectroscopy. Quantitative binding measurements indicate that the TEMPO moiety does not significantly perturb the affinity of the cellooligo-saccharide derivatives for the CBDs. The paramagnetic enhancements of the amide H-1(N) longitudinal (Delta R-1) and transverse (Delta R-2) relaxation rates were measured by comparing the effects of TEMPO-cellotetraose in its nitroxide (oxidized) and hydroxylamine (reduced) forms on the two CBDs. The bound spin-label affects most significantly the relaxation rates of amides located at both ends of the sugar-binding cleft of each CBD. Similar results are observed with TEMPO-cellotriose bound to CBDN1. This demonstrates that the TEMPO-labeled cellooligosaccharides, and by inference strands of amorphous cellulose, can associate with CBDN1 and CBDN2 in either orientation across their beta-sheet binding clefts. The ratio of the association constants for binding in each of these two orientations is estimated to be within a factor of five to tenfold. This finding is consistent with the approximate symmetry of the hydrogen-bonding groups on both the cellooligosaccharides and the residues forming the binding clefts of the CenC CBDs. (C) 1999 Academic Press.},
	keywords = {CELLULASES, ENDOGLUCANASE, GLYCOSYNTHASE, MAGNETIC-RESONANCE SPECTROSCOPY, NMR, protein-carbohydrate interaction, PROTEINS, SENSITIVITY, SITE, SPECIFICITY, spin label},
	isbn = {0022-2836},
	url = {<Go to ISI>://000079626300013},
	author = {Johnson, P. E. and Brun, E. and Mackenzie, L. F. and Withers, S. G. and McIntosh, L. P.}
}
@article {4406,
	title = {Assigning the NMR spectra of aromatic amino acids in proteins: analysis of two Ets pointed domains},
	journal = {Biochemistry and Cell Biology-Biochimie Et Biologie Cellulaire},
	volume = {76},
	number = {2-3},
	year = {1998},
	note = {ISI Document Delivery No.: 157QRTimes Cited: 11Cited Reference Count: 34},
	pages = {379-390},
	type = {Article},
	abstract = {The measurement of interproton nuclear Overhauser enhancements (NOEs) and dihedral angle restraints of aromatic amino acids is a critical step towards determining the structure of a protein. The complete assignment of the resonances from aromatic rings and the subsequent resolution and identification of their associated NOEs, however, can be a difficult task. Shown here is a strategy for assigning the H-1,C-13, and N-15 signals from the aromatic side chains of histidine, tryptophan, tyrosine, and phenylalanine using a suite of homo- and hetero-nuclear scalar and NOE correlation experiments, as well as selective deuterium isotope labelling. In addition, a comparison of NOE information obtained from homonuclear NOE spectroscopy (NOESY) and C-13-edited NOESY - heteronuclear single quantum correlation experiments indicates that high-resolution homonuclear two-dimensional NOESY spectra of selectively deuterated proteins are invaluable for obtaining distance restraints to the aromatic residues.},
	keywords = {ACTIVE-SITE, ANGLE, aromatic residue, BACKBONE H-1, C-13-LABELED PROTEINS, CHEMICAL-SHIFTS, dihedral, DNA-BINDING, HETERONUCLEAR NMR, HISTIDINE-RESIDUES, MAGNETIC-RESONANCE SPECTROSCOPY, NMR assignment, NOE, pH titration, PHENYLALANINE RESIDUES, TRANSCRIPTION FACTOR},
	isbn = {0829-8211},
	url = {<Go to ISI>://000078073600026},
	author = {Slupsky, C. M. and Gentile, L. N. and McIntosh, L. P.}
}
