Structural characterisation of xyloglucan secreted by suspension-cultured cells of Nicotiana plumbaginifolia

Linkage analysis of a xyloglucan from the extracellular medium of suspension cultures of Nicotiana plumbaginifolia showed mostly 4-Glcp and 4,6-Glcp, terminal Xylp and 2-Xylp, and terminal Araf, along with ~10% (w/w) O-acetyl groups, equivalent to ~ 0.28 mol acetyl per mol of glycosyl residue. Methylation with methyl trifluoromethanesulfonate under neutral conditions, followed by re-methylation with CD3I under basic conditions, and conversion into partially methylated alditol acetates showed that O-acetyl groups were primarily attached to C-6 of ~44% of the 4-Glcp backbone not substituted with Xylp residues and to C-5 of ~15% of the terminal Araf residues. These positions of the O-acetyl groups were confirmed by 1H-NMR. Oligosaccharides generated by digestion of native xyloglucan with endo-(1 → 4)-β-glucanase were separated by a combination of gel-filtration chromatography and anion-exchange HPLC, and analysed by glycosyl linkage analysis and by electrospray ionisation-mass spectrometry (ESI-MS). The major oligosaccharide subunits were Glc4Xyl2 and Glc5Xyl2, of which 50-60% are substituted with one terminal Araf residue attached to O-2 of a Xylp residue, and a further 20-25% are substituted with two terminal Araf residues attached to O-2 of the Xylp residues. ESI-MS showed that many of the oligosaccharide subunits carried one, two and, occasionally three O-acetyl groups.

Structural characterisation of xyloglucan secreted by suspension-cultured cells of Nicotiana plumbaginifolia

Linkage analysis of a xyloglucan from the extracellular medium of suspension cultures of Nicotiana plumbaginifolia showed mostly 4-Glcp and 4,6-Glcp, terminal Xylp and 2-Xylp, and terminal Araf, along with ~10% (w/w) O-acetyl groups, equivalent to ~ 0.28 mol acetyl per mol of glycosyl residue. Methylation with methyl trifluoromethanesulfonate under neutral conditions, followed by re-methylation with CD3I under basic conditions, and conversion into partially methylated alditol acetates showed that O-acetyl groups were primarily attached to C-6 of ~44% of the 4-Glcp backbone not substituted with Xylp residues and to C-5 of ~15% of the terminal Araf residues. These positions of the O-acetyl groups were confirmed by 1H-NMR. Oligosaccharides generated by digestion of native xyloglucan with endo-(1 → 4)-β-glucanase were separated by a combination of gel-filtration chromatography and anion-exchange HPLC, and analysed by glycosyl linkage analysis and by electrospray ionisation-mass spectrometry (ESI-MS). The major oligosaccharide subunits were Glc4Xyl2 and Glc5Xyl2, of which 50-60% are substituted with one terminal Araf residue attached to O-2 of a Xylp residue, and a further 20-25% are substituted with two terminal Araf residues attached to O-2 of the Xylp residues. ESI-MS showed that many of the oligosaccharide subunits carried one, two and, occasionally three O-acetyl groups.

Chlorido(η6-N2-diphenylphosphanyl-N1,N1-diisopropyl-4-methoxybenzamidine-κP)(triphenylphosphane-κP)ruthenium(II) trifluoromethansulfonate acetone disolvate

In the title compound, [RuCl(C18H15P)(C26H31N2OP)](CF3O3S)·2C3H6O, the RuIIion is coordinated in a three-legged piano stool, half-sandwich-type geometry by a chlorido ligand, a triphenylphosphine and a tethered η6-(phenyl-p-O-methoxy) κ1-P N-diphenylphosphinoN′-diisopropyl amidine ligand charge-balanced by a trifluormethansulfonate counter-anion. The η6-coordination mode of the arene incorporated into the structure was generatedin situafter addition of methyl trifluoromethanesulfonate to the neutral η5-arene tethered precursor complex [RuCl(PPh3)(η5:κ1-OC6H4C(NiPr2)=N-PPh2)] in dichloromethane solution.