@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.}
}
