Supramolecular chemical shift reagents inducing conformational transition: NMR analysis of carbohydrate homooligomer mixtures

Transcription

1 Electronic Supplementary Material (ESI) for ChemComm. This journal is The Royal Society of Chemistry 2015 Supramolecular chemical shift reagents inducing conformational transition: NMR analysis of carbohydrate homooligomer mixtures Sophie R. Beeren* a and Sebastian Meier* b Supporting Information Contents S1 Materials S1 S2 NMR spectroscopy S3 S1 Materials Glucose, maltose, maltotriose, maltotetraose, maltopentaose, maltohexaose, 8-hydroxypyrene- 1,3,6-trisulfonic acid trisodium salt (HPTS) and sodium dodecyl sulfate (SDS) were obtained from Sigma Aldrich. Maltoheptaose and maltooctaose were obtained from Carbosynth (Compton, UK). D 2 O was purchased from Cambridge Isotope Laboratories, (Andover, MA, USA). HPTS-C 16, HPTS-C 12, HPTS-C 8 and HPTS-C 4 were synthesized as described previously. 1,2 The maltooligosaccharide mixture was prepared by fractional precipitation of a starch digest with ethanol as described previously. 3 The distribution of maltooligosaccharides in the mixture was determined using UPLC/MS analysis following fluorescence labelling at the reducing end with 2-aminobenzamide as described previously. 2 S1

2 DP 5 DP 10 DP 15 DP 20 Figure S1. Fluorescence chromatogram showing UPLC analysis of the α(1-4) glucan mixture used in this work. S2

3 S2 NMR spectroscopy 1 H- 13 C HSQC NMR spectra were recorded on an 800 MHz Bruker (Fällanden, Switzerland) Avance spectrometer equipped with a 5 mm TCI z-gradient CryoProbe and an 18.7 T magnet (Oxford Magnet Technology, Oxford, UK) and processed with Topspin 3.0 (Bruker) using extensive zero filling in both dimension, no linear prediction and mild resolution enhancement in the 13 C dimension. Sensitivity enhanced 1 H- 13 C HSQC spectra were acquired with narrow spectral width in the indirect dimension using the standard Bruker pulse sequence (hsqcetgpsi). Specifically: For analysis of the α-glucan mixture with 10 mm HPTS-C 16, SDS or HPTS HSQC spectra were acquired as matrices of complex data points sampling 143 milliseconds in the direct ( 1 H) and 319 milliseconds in the indirect ( 13 C) dimension. The spectra were acquired with a spectral width of 9 ppm (7183 Hz) in the direct dimension and of 4 ppm (803 Hz) in the indirect dimension with a recycle delay of 1 second. For analysis of the α-glucan mixture alone and in the presence of HPTS, 2 scans were accumulated. The resolved spectra of the α-glucan mixture in the presence of 10 mm HPTS-C 16 and 10 mm SDS were recorded over night with 96 scans. One-dimensional 1 H NMR spectra of the mixture alone and in the presence of 10 mm SDS, HPTS and HPTS-C 16 are shown in Figure S2. Spectra were acquired at 800 MHz by sampling complex data points for an acquisition time of 1.27 seconds and employing a spectral width of Hz. 1 H NMR spectra were processed with extensive zero filling and with an exponential line broadening of 0.3 Hz. For analysis of the α-glucan mixture together with HPTS-C 12, HPTS-C 8 and HPTS-C 4 : HSQC spectra were acquired as matrices of complex data points sampling 143 milliseconds in the direct ( 1 H) and 319 milliseconds in the indirect ( 13 C) dimension by accumulating 96 scans for HPTS-C 12 and HPTS-C 8 with a recycle delay of 1 second and by accumulating 76 scans in the case of HPTS-C 4 with a recycle delay of 1 second. For assignment of signals using commercial reference compounds: Mixtures of G 1, G 2, G 3, G 6 and G 8 (each 2 mg/ml) and of G 2, G 4, G 5, G 6 and G 7 (each 2 mg/ml) were prepared and subjected to HSQC spectroscopy for the validation of mixture S3

4 signal assignments by the use of reference compounds. Both mixtures were analysed in the presence of 10 mm (i) HPTS-C 4, (ii) HPTS-C 8, (iii) HPTS-C 12 or (iv) HPTS-C 16 (Figure S5). The HSQC spectra were acquired as matrices of complex data points sampling 143 milliseconds in the direct ( 1 H) and 319 milliseconds in the indirect ( 13 C) dimension. Spectra were recorded with a spectral width of 9 ppm (7183 Hz) in the direct dimension and of 4 ppm (803 Hz) in the indirect dimension with a recycle delay of 1 second and 8 scans. (a) α(1-4) glucan mixture (b) +10 mm SDS (c) +10 mm HPTS (d) +10 mm HPTS-C Chemical Shift ( 1 H, ppm) Figure S2. 1 H NMR spectra (300 K, 800 MHz, D 2 O) of the α(1-4) glucan mixture alone (a) and in the presence of 10 mm SDS (b), HPTS (c), and HPTS-C 16 (d). Anomeric regions of the corresponding HSQC spectra are shown in panels a-d of the main text Figure 2. S4

5 H1 H1β-red H1α-red H2β-red H5β-red H1α-red H1β-red H1 H2β-red H5β-red Figure S3. 1H13C HSQC spectra (300K, 800 MHz, D2O) of the α(1-4) glucan mixture alone (a) and in the presence of 10 mm HPTS-C16 (b). The spectra were recorded with a narrow (2 and 4 ppm) sweep width in the 13C dimension and therefore many signals are multiply aliased. S5

6 (a) (b) Figure S4. 1 H 13 C HSQC spectra (300 K, 800 MHz, D 2 O) showing (a) H1β reducing end signals and (b) the H5β reducing end signals of the 10 mg/ml α(1 4) glucan mixture in the presence of 10 mm of (i) HPTS-C 4, (ii) HPTS-C 8, (iii) HPTS-C 12 and (iv) HPTS-C 16. S6

7 (a) (b) (c) Figure S5. 1 H 13 C HSQC spectra (300 K, 800 MHz, D 2 O) showing (a) the H1β reducing end signals, (b) the H2β reducing end signals and (c) the H5β reducing end signals of: in red, a mixture of G 1, G 2, G 3, G 6 and G 8 (each 2 mg/ml) and in blue, a mixture of G 2, G 4, G 5, G 6 and G 7 (each 2 mg/ml) in the presence of 10 mm (i) HPTS-C 4 or (ii) HPTS-C 8, (iii) HPTS-C 12 and (iv) HPTS-C Beeren, S. R.; Hindsgaul, O. Angew. Chem. Int. Ed. 2013, 52, Beeren, S. R.; Meier, S.; Hindsgaul, O. Chem. Eur. J. 2013, 19, Johannesen, S. A.; Beeren, S. R.; Blank, D.; Yang, B. Y.; Geyer, R.; Hindsgaul, O. Carbohydr. Res. 2012, 352, S7