The conformation of Xylβ1-(Manα1-3)2Manβ1-4Glcβ1-OCH 2CH(N 3)CH(OH) CHCHC 13H 27 tetrasaccharide glycoside in Me 2SO- d 6 was investigated with use of a distance mapping procedure based on rotating-frame NOE and hydrogen bond constraints, and Molecular Mechanics calculations. The Manα1-3Manβ linkage was found to be well defined in a single conformation, whereas some flexibility could he assumed for the remaining two glycosidic linkages. Similar conclusions, though based on a smaller number of constraints, were drawn for the title compound anchored in mixed D 2O/dodecylphosphocholine- d 38 micelles.