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Exploration of the active site of β4GalT7 – Synthesis of substrates and inhibitors

Thorsheim, Karin LU (2017)
Abstract (Swedish)
Ytan av alla celler är dekorerad med kolhydrater som står för mycket av den information en cell överför till omgivande celler. Många av kolhydraterna tillhör en föreningsklass som kallas proteoglykaner som består av ett protein sammanbundet med en eller flera långa kolhydratkedjor. Dessa kolhydratkedjor kallas glykosaminoglykaner och är bundna till proteinet via kolhydraten xylos. Än så länge har vi bara en vag aning om sambanden mellan strukturen hos glykosaminoglykanerna och den information de överför. Denna avhandling handlar om att skapa verktyg som kan ge oss insikter i hur glykosaminoglykanerna bildas.
Xylosider, det vill säga molekyler baserade på xylos kopplat till en annan molekyl – en aglykon, kan gå in i celler och starta... (More)
Ytan av alla celler är dekorerad med kolhydrater som står för mycket av den information en cell överför till omgivande celler. Många av kolhydraterna tillhör en föreningsklass som kallas proteoglykaner som består av ett protein sammanbundet med en eller flera långa kolhydratkedjor. Dessa kolhydratkedjor kallas glykosaminoglykaner och är bundna till proteinet via kolhydraten xylos. Än så länge har vi bara en vag aning om sambanden mellan strukturen hos glykosaminoglykanerna och den information de överför. Denna avhandling handlar om att skapa verktyg som kan ge oss insikter i hur glykosaminoglykanerna bildas.
Xylosider, det vill säga molekyler baserade på xylos kopplat till en annan molekyl – en aglykon, kan gå in i celler och starta eller blockera bildandet av glykosaminoglykaner genom att efterlikna det naturliga substratet för ett visst enzym – β4GalT7. För att öka förståelsen för hur en xylosid ska se ut för att vara ett bra substrat eller en bra hämmare för β4GalT7 har vi syntetiserat och testat aktiviteten av olika xylosider.
Vi har valt att systematiskt undersöka tre olika delar av xylosidmolekylerna - själva kolhydraten, kopplingen och aglykonen. Vi har hittat ett antal nya molekyler som fungerar som bra substrat för β4GalT7 och vi har också hittat substanser som fungerar som hämmare.
Resultaten i den här avhandlingen lägger en grund för vilka strukturelement som kan inkorporeras i xylosider för att ge effektiva substrat samt grundläggande krav för en hämmare.
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Abstract
β-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the biosynthesis of proteoglycans (PGs) and glycosaminoglycan (GAG) chains, which are important macromolecules involved in many biological processes such as cell growth and cell signaling as well as in cancer pathobiology and viral and bacterial infections. Despite its pivotal role, much is still unknown regarding the specific structure of GAGs and how the structure affects its functions. GAG synthesis can be regulated by xylosides acting on β4GalT7 as either substrates or inhibitors. In an effort to find efficient substrates and inhibitors of β4GalT7, which would be valuable tools applicable in GAG research, we set out to investigate the active site of β4GalT7 by synthesizing and... (More)
β-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the biosynthesis of proteoglycans (PGs) and glycosaminoglycan (GAG) chains, which are important macromolecules involved in many biological processes such as cell growth and cell signaling as well as in cancer pathobiology and viral and bacterial infections. Despite its pivotal role, much is still unknown regarding the specific structure of GAGs and how the structure affects its functions. GAG synthesis can be regulated by xylosides acting on β4GalT7 as either substrates or inhibitors. In an effort to find efficient substrates and inhibitors of β4GalT7, which would be valuable tools applicable in GAG research, we set out to investigate the active site of β4GalT7 by synthesizing and examining xylosides and xyloside analogs with modifications in the xylose moiety, the endocyclic and exocyclic positions, as well as the aglycon. The overarching aim with these investigations was to pinpoint the requirements of efficient substrates and efficient inhibitors. The synthesized compounds were evaluated in a β4GalT7 assay in combination with molecular docking simulations and conformational analysis by NMR spectroscopy. We found that efficient substrates are formed when keeping the xylose moiety unmodified, but exchanging the endocyclic and/or exocyclic oxygen atoms for sulfur, as well as connecting the xyloside to an aglycon consisting of a fused aromatic system, preferably separated from the xylose part by a short oligoethylene glycol spacer. These structural features can not directly be transferred to a xyloside analog possessing inhibitory activity to gain efficient inhibitors of β4GalT7. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Associate Professor Sandström, Anja, Uppsala University, Department of Medicinal Chemistry
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Xylosides, β4GalT7, β-1,4-galactosyltransferase 7, glycosaminoglycan, synthesis
pages
226 pages
publisher
Lund University, Faculty of Science, Department of Chemistry
defense location
Lecture hall A, Center for chemistry and chemical engineering, Naturvetarvägen 14, Lund
defense date
2017-09-15 9:00
ISBN
978-91-7422-535-8
language
English
LU publication?
yes
id
c9518749-4ded-4245-bad3-3ea9ec1368db
date added to LUP
2017-08-22 09:38:37
date last changed
2017-08-29 16:30:42
@phdthesis{c9518749-4ded-4245-bad3-3ea9ec1368db,
  abstract     = {β-1,4-Galactosyltransferase 7 (β4GalT7) is a key enzyme in the biosynthesis of proteoglycans (PGs) and glycosaminoglycan (GAG) chains, which are important macromolecules involved in many biological processes such as cell growth and cell signaling as well as in cancer pathobiology and viral and bacterial infections. Despite its pivotal role, much is still unknown regarding the specific structure of GAGs and how the structure affects its functions. GAG synthesis can be regulated by xylosides acting on β4GalT7 as either substrates or inhibitors. In an effort to find efficient substrates and inhibitors of β4GalT7, which would be valuable tools applicable in GAG research, we set out to investigate the active site of β4GalT7 by synthesizing and examining xylosides and xyloside analogs with modifications in the xylose moiety, the endocyclic and exocyclic positions, as well as the aglycon. The overarching aim with these investigations was to pinpoint the requirements of efficient substrates and efficient inhibitors. The synthesized compounds were evaluated in a β4GalT7 assay in combination with molecular docking simulations and conformational analysis by NMR spectroscopy. We found that efficient substrates are formed when keeping the xylose moiety unmodified, but exchanging the endocyclic and/or exocyclic oxygen atoms for sulfur, as well as connecting the xyloside to an aglycon consisting of a fused aromatic system, preferably separated from the xylose part by a short oligoethylene glycol spacer. These structural features can not directly be transferred to a xyloside analog possessing inhibitory activity to gain efficient inhibitors of β4GalT7.},
  author       = {Thorsheim, Karin},
  isbn         = {978-91-7422-535-8},
  keyword      = {Xylosides,β4GalT7,β-1,4-galactosyltransferase 7,glycosaminoglycan,synthesis},
  language     = {eng},
  pages        = {226},
  publisher    = {Lund University, Faculty of Science, Department of Chemistry},
  school       = {Lund University},
  title        = {Exploration of the active site of β4GalT7 – Synthesis of substrates and inhibitors},
  year         = {2017},
}