Structure of Pullulan Polysaccharide by Magnetic Resonance Spectroscopy (NMR)
Poster Number
15A
Research or Creativity Area
Natural Sciences
Abstract
Pullulan is a polysaccharide made of three glucose units connected by α-1,6 and α-1,4 glycosidic linkages1. The primary and secondary structure of pullulan was investigated through NMR experiments using the JEOL ECA-600 instrument. Pullulan is a unique polysaccharide that is flexible, non-toxic, anti-bacterial, biodegradable, and has adhesive properties, making it useful in diverse industries. Namely, pullulan has been used as a hydrogel in wound dressings, drug delivery devices, and reducing inflammation in the oral cavity1,2. Pullulan has unique properties due to its chemical structure as seen through our experiments. Magnetic Resonance spectroscopy (NMR) is a powerful analytical technique that can reveal coupling constants between neighboring atoms and how polysaccharides behave in solution, especially water4. The hydrogen bond interaction between pullulan and water is like that found in the secondary structure of proteins to form alpha helices and beta-pleated sheets. Coupling constants in pullulan, including those from OH-groups, were investigated in multiple solvents (D2O, H2O, DMSO) at different temperatures. Water-free DMSO was used to make OH-resonances visible. In addition, the building blocks of pullulan (maltose and isomaltose) were investigated. So-called H/D-isotope exchange reactions on the OH-groups caused chemical shift isotope effects on neighboring 13C-signals. A hydrogen bond between the two rings of maltose was detected, and directionality of the hydrogen bond was elucidated and confirmed by molecular modeling. Moreover, digestion of pullulan by pullulanase enzyme was also performed (~40℃, pH ~5.0). Digest fragments of pullulan and structurally similar amylose were generated with inexpensive, commercial pullulanase and seen in HPLC as investigated in a separate project5. Our study concluded that the enzyme performed best at pH 5.5 (55℃) and at a pullulan-to-enzyme ratio of 100 mg : 1 μL in 500 μL total buffer volume. Enzyme preference for the α-1,6-linkage in pullulan was observed.
Literature:
- Vipul D. Prajapati et al., Carbohydr. Polymers, 95, 2013, 540-549.
- Elangwe, C. N., Morozkina, S. N., Olekhnovich, R. O., Polyakova, V. O., Krasichkov, A., Yablonskiy, P. K., & Uspenskaya, M. V. (2023). Pullulan-Based Hydrogels in Wound Healing and Skin Tissue Engineering Applications: A Review. International journal of molecular sciences, 24(5), 4962.
- Li, Y., Bi, D., Hu, Z., Yang, Y., Liu, Y., & Leung, W. K. (2023). Hydrogel-Forming Microneedles with Applications in Oral Diseases Management. Materials (Basel, Switzerland), 16(13), 4805.
- Carolina Fontana and Göran. Widmalm Chemical Reviews 2023 123 (3), 1040-1102. DOI: 10.1021/acs.chemrev.2c00580.
- Ella Nguyen et al., PURCC, University of the Pacific, 2024 (poster)
Location
Don and Karen DeRosa University Center (DUC) Poster Hall
Start Date
27-4-2024 10:30 AM
End Date
27-4-2024 12:30 PM
Structure of Pullulan Polysaccharide by Magnetic Resonance Spectroscopy (NMR)
Don and Karen DeRosa University Center (DUC) Poster Hall
Pullulan is a polysaccharide made of three glucose units connected by α-1,6 and α-1,4 glycosidic linkages1. The primary and secondary structure of pullulan was investigated through NMR experiments using the JEOL ECA-600 instrument. Pullulan is a unique polysaccharide that is flexible, non-toxic, anti-bacterial, biodegradable, and has adhesive properties, making it useful in diverse industries. Namely, pullulan has been used as a hydrogel in wound dressings, drug delivery devices, and reducing inflammation in the oral cavity1,2. Pullulan has unique properties due to its chemical structure as seen through our experiments. Magnetic Resonance spectroscopy (NMR) is a powerful analytical technique that can reveal coupling constants between neighboring atoms and how polysaccharides behave in solution, especially water4. The hydrogen bond interaction between pullulan and water is like that found in the secondary structure of proteins to form alpha helices and beta-pleated sheets. Coupling constants in pullulan, including those from OH-groups, were investigated in multiple solvents (D2O, H2O, DMSO) at different temperatures. Water-free DMSO was used to make OH-resonances visible. In addition, the building blocks of pullulan (maltose and isomaltose) were investigated. So-called H/D-isotope exchange reactions on the OH-groups caused chemical shift isotope effects on neighboring 13C-signals. A hydrogen bond between the two rings of maltose was detected, and directionality of the hydrogen bond was elucidated and confirmed by molecular modeling. Moreover, digestion of pullulan by pullulanase enzyme was also performed (~40℃, pH ~5.0). Digest fragments of pullulan and structurally similar amylose were generated with inexpensive, commercial pullulanase and seen in HPLC as investigated in a separate project5. Our study concluded that the enzyme performed best at pH 5.5 (55℃) and at a pullulan-to-enzyme ratio of 100 mg : 1 μL in 500 μL total buffer volume. Enzyme preference for the α-1,6-linkage in pullulan was observed.
Literature:
- Vipul D. Prajapati et al., Carbohydr. Polymers, 95, 2013, 540-549.
- Elangwe, C. N., Morozkina, S. N., Olekhnovich, R. O., Polyakova, V. O., Krasichkov, A., Yablonskiy, P. K., & Uspenskaya, M. V. (2023). Pullulan-Based Hydrogels in Wound Healing and Skin Tissue Engineering Applications: A Review. International journal of molecular sciences, 24(5), 4962.
- Li, Y., Bi, D., Hu, Z., Yang, Y., Liu, Y., & Leung, W. K. (2023). Hydrogel-Forming Microneedles with Applications in Oral Diseases Management. Materials (Basel, Switzerland), 16(13), 4805.
- Carolina Fontana and Göran. Widmalm Chemical Reviews 2023 123 (3), 1040-1102. DOI: 10.1021/acs.chemrev.2c00580.
- Ella Nguyen et al., PURCC, University of the Pacific, 2024 (poster)
