Sökning: WFRF:(Karlsson Christina)
> (2015-2019) >
Characterization an...
Characterization and engineering of carbohydrate-active enzymes for biotechnological applications
-
- Hassan, Noor, 1977- (författare)
- KTH,Industriell bioteknologi,Christina Divne
-
- Divne, Christina, Docent (preses)
- KTH,Industriell bioteknologi
-
- Nordberg Karlsson, Eva, Professor (opponent)
- Lunds Universitet, Sweden
-
(creator_code:org_t)
- ISBN 9789175955117
- Stockholm : KTH Royal Institute of Technology, 2015
- Engelska 57 s.
-
Serie: TRITA-BIO-Report, 1654-2312 ; 2015:8
- Relaterad länk:
-
https://kth.diva-por... (primary) (Raw object)
-
visa fler...
-
https://urn.kb.se/re...
-
visa färre...
Abstract
Ämnesord
Stäng
- Extremozymes are enzymes produced by microorganisms that live in extreme habitats. Due to their higher stability, extremozymes is attracting interest as biocatalysts in various industrial processes. In this context, carbohydrate-active extremozymes can be used in various processes relevant to the paper, food and feed industry.In this thesis, the crystal structure, biochemical characterization and the capacity to synthesize prebiotic galacto-oligosaccharides (GOS) were investigated for a β-glucosidase (HoBGLA) from the halothermophilic bacterium Halothermothrix orenii. The wild-type enzyme displays favorable characteristics for lactose hydrolysis and produces a range of prebiotic GOS, of which β-D-Galp-(1→6)-D-Lac and β-D-Galp-(1→3)-D-Lac are the major products (Paper I).To further improve GOS synthesis by HoBGLA, rational enzyme engineering was performed (Paper II). Six enzyme variants were generated by replacing strategically positioned active-site residues. Two HoBGLA variants were identified as potentially interesting, F417S and F417Y. The former appears to synthesize one particular GOS product in higher yield, whereas the latter produces a higher yield of total GOS.In Paper III, the high-resolution crystal structure and biochemical characterization of a hemicellulase (HoAraf43) from H. orenii is presented. HoAraf43 folds as a five-bladed β-propeller and displays α-Larabinofuranosidase activity. The melting temperature of HoAraf43 increases significantly in the presence of high salt and divalent cations, which is consistent with H. orenii being a halophile.Furthermore, the crystal structures of a thermostable tetrameric pyranose 2-oxidase from Phanerochaete chrysosporium (PcP2O) were determined to investigate the structural determinants of thermostability (Paper IV). PcP2O has an increased number of salt links between subunits, which may provide a mechanism for increased stability. The structures also imply that the N-terminal region acts as an intramolecular chaperone during homotetramer assembly.
Ämnesord
- NATURVETENSKAP -- Biologi -- Strukturbiologi (hsv//swe)
- NATURAL SCIENCES -- Biological Sciences -- Structural Biology (hsv//eng)
Nyckelord
- se conversion
- galacto-oligosaccharides
- thermostability
- propeptide
- Bioteknologi
- Biotechnology
Publikations- och innehållstyp
- vet (ämneskategori)
- dok (ämneskategori)
Hitta via bibliotek
Till lärosätets databas