The hexopyranosyl residue that is C-glycosidically linked to the side chain of tryptophan-7 in human RNase Us is alpha-mannopyranose.
Recently, the novel C-glycosidic linkage of a hexopyranosyl residue to the indole ring of tryptophan residue 7 of human RNase U(s) was reported [Hofsteenge, J., Müller, D. R., de Beer, T., Löffler A., Richter, W. J., & Vliegenthart, J. F. G. (1994) Biochemistry 33, 13524-13530]. Identification of this monosaccharide is a prerequisite for studies of its biosynthesis and its biological relevance. Using vicinal proton-proton coupling constants and rotating-frame nuclear Overhauser enhancements, ewe demonstrate that the C-linked substituent is alpha-mannopyranose. Furthermore, the nuclear magnetic resonance (NMR) data indicate that the mannopyranose moiety in a glycopeptide derived from RNase U(s) adopts several conformations on the NMR time scale.
de Beer
T
T
Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands.
Vliegenthart
J F
JF
Löffler
A
A
Hofsteenge
J
J
D000595:Amino Acid Sequence; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D004722:Endoribonucleases / Q000737:chemistry*; D006031:Glycosylation; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000737:chemistry*; D008969:Molecular Sequence Data; D015394:Molecular Structure; D014312:Trisaccharides / Q000737:chemistry; D014364:Tryptophan / Q000737:chemistry
D014312:Trisaccharides; D014364:Tryptophan; D004722:Endoribonucleases; C029494:ribonuclease U; D008358:Mannose