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Measurement of long‐range2 13 C‐ 1 H coupling constants of 95% uniformly 13 C‐labeled polysaccharide from streptococcus mitis J22
Author(s) -
Gitti Rossitza,
Long Guixia,
Bush C. Allen
Publication year - 1994
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360341005
Subject(s) - homonuclear molecule , glycosidic bond , chemistry , nuclear magnetic resonance spectroscopy , coupling constant , nmr spectra database , nuclear overhauser effect , two dimensional nuclear magnetic resonance spectroscopy , crystallography , j coupling , depolymerization , analytical chemistry (journal) , carbon 13 , stereochemistry , spectral line , molecule , organic chemistry , astronomy , enzyme , quantum mechanics , physics , particle physics
Abstract The coaggregation of Streptococcus mitis strain J22 in the early stages of dental plaque formation has been shown to result from interaction of cell wall polysaccharides with lectins on the surface of other oral bacterial species. This bacterium was grown in a medium containing 13 C as the sole carbon source. We have isolated the lectin receptor polysaccharide from this strain with full enrichment in 13 C and have determined a number of two‐bond and three‐bond 13 C‐ 1 H coupling constants from measurements of the offsets in two‐dimensional homonuclear nmr spectra [exclusive correlated spectroscopy (E‐COSY) method]. A scheme for reliable extraction of these coupling constants from homonuclear Hartmann‐Hahn and nuclear Overhauser effect spectroscopy spectra is tested in model compounds. We interpret the three‐bond coupling across the glycosidic linkage in terms of dihedral angles in order to provide conformational information to supplement molecular modeling and nuclear Overhauser effect data. We show that the E‐COSY method works well even for coupling constants smaller than the nmr line width and that a number of the 3 J CH across the glycosidic linkage are in the range of 1–2 Hz, which is much smaller than many previously reported values. © 1994 John Wiley & Sons, Inc.