Advanced

Synthesis of glycosylated amino acids. Solid-phase assembly of T-cell immunogenic glycopeptides and fragments from HIV gp120

Elofsson, Mikael (1996)
Abstract
Synthetic glycopeptides are valuable tools for studies of the biological functions of protein-bound carbohydrates. Today glycopeptides are efficiently prepared by solid-phase synthesis according to the 9-fluorenylmethoxycarbonyl (Fmoc) protocol, provided that suitable glycosylated amino acids are available.



In this thesis commercial or readily accessible carbohydrate 1,2-trans peracetates were used as glycosyl donors in boron trifluoride etherate or stannic chloride promoted glycosylations of mercapto or hydroxyl groups of 3-mercaptopropionic acid and Fmoc-amino acids having unprotected carboxyl groups. The 1,2-trans glycosylated building blocks were isolated in 37-90% yields. Without further protective group... (More)
Synthetic glycopeptides are valuable tools for studies of the biological functions of protein-bound carbohydrates. Today glycopeptides are efficiently prepared by solid-phase synthesis according to the 9-fluorenylmethoxycarbonyl (Fmoc) protocol, provided that suitable glycosylated amino acids are available.



In this thesis commercial or readily accessible carbohydrate 1,2-trans peracetates were used as glycosyl donors in boron trifluoride etherate or stannic chloride promoted glycosylations of mercapto or hydroxyl groups of 3-mercaptopropionic acid and Fmoc-amino acids having unprotected carboxyl groups. The 1,2-trans glycosylated building blocks were isolated in 37-90% yields. Without further protective group manipulations the glycosylated building blocks were employed in solid-phase synthesis of N-terminally or internally glycosylated derivatives of helper T-cell stimulatory peptides from hen-egg lysozyme (HEL).



Fmoc-serine glycosylated with beta-D-lactose was used in solid-phase synthesis of a water-soluble glycosphingolipid analogue which can be covalently immobilized on solid phases or coupled to carrier proteins.



The Tn [alpha-GalNAc-(1-O)-Ser/Thr] and sialyl Tn [alpha-NeuNAc-(1-6)-alpha-GalNAc-(1-O)-Ser/Thr] epitopes are important antigens on cancer cells and the HIV envelope glycoprotein gp120. Tn and sialyl Tn building blocks were prepared and employed in solid-phase synthesis of fragments from gp120. Our results show that peptides glycosylated with acid-labile sialic acids can be synthesized by solid-phase techniques and purified by reversed-phase HPLC. The GalNAc unit of the Tn building block was protected with acid-labile protective groups, hence avoiding a separate base-mediated carbohydrate deprotection step.



The glycosylated HEL peptides were evaluated for binding to major histocompatibility complex class II (MHC II) molecules and the immune response to those glycopeptides bound by MHC II molecules was then investigated. Immunization of mice with glycopeptides gave helper T-cells with specificity for the carbohydrate moiety. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Oscarson, Stefan, Organic Chemistry, Stockholm University
publishing date
type
Thesis
publication status
published
subject
keywords
HIV, immunogenic glycopeptides, T-cell, MHC, solid-phase glycopeptide synthesis, glycopeptides, glycoside synthesis, glycosylated amino acids, gp120, neoglycosphingolipids, Organic chemistry, Organisk kemi
pages
94 pages
publisher
Organic Chemistry, Lund University
defense location
K:D, Center for Chemistry and Chemical Engineering, Lund, Sweden
defense date
1996-05-24 10:15
external identifiers
  • Other:LUTKDH/(TKOK-1038)/1-94/(1996)
ISBN
91-628-2103-2
language
English
LU publication?
no
id
df13e4d2-06f1-4108-b76c-b1bee5bf7cbb (old id 28438)
date added to LUP
2007-06-12 14:05:21
date last changed
2016-09-19 08:45:03
@phdthesis{df13e4d2-06f1-4108-b76c-b1bee5bf7cbb,
  abstract     = {Synthetic glycopeptides are valuable tools for studies of the biological functions of protein-bound carbohydrates. Today glycopeptides are efficiently prepared by solid-phase synthesis according to the 9-fluorenylmethoxycarbonyl (Fmoc) protocol, provided that suitable glycosylated amino acids are available.<br/><br>
<br/><br>
In this thesis commercial or readily accessible carbohydrate 1,2-trans peracetates were used as glycosyl donors in boron trifluoride etherate or stannic chloride promoted glycosylations of mercapto or hydroxyl groups of 3-mercaptopropionic acid and Fmoc-amino acids having unprotected carboxyl groups. The 1,2-trans glycosylated building blocks were isolated in 37-90% yields. Without further protective group manipulations the glycosylated building blocks were employed in solid-phase synthesis of N-terminally or internally glycosylated derivatives of helper T-cell stimulatory peptides from hen-egg lysozyme (HEL).<br/><br>
<br/><br>
Fmoc-serine glycosylated with beta-D-lactose was used in solid-phase synthesis of a water-soluble glycosphingolipid analogue which can be covalently immobilized on solid phases or coupled to carrier proteins.<br/><br>
<br/><br>
The Tn [alpha-GalNAc-(1-O)-Ser/Thr] and sialyl Tn [alpha-NeuNAc-(1-6)-alpha-GalNAc-(1-O)-Ser/Thr] epitopes are important antigens on cancer cells and the HIV envelope glycoprotein gp120. Tn and sialyl Tn building blocks were prepared and employed in solid-phase synthesis of fragments from gp120. Our results show that peptides glycosylated with acid-labile sialic acids can be synthesized by solid-phase techniques and purified by reversed-phase HPLC. The GalNAc unit of the Tn building block was protected with acid-labile protective groups, hence avoiding a separate base-mediated carbohydrate deprotection step.<br/><br>
<br/><br>
The glycosylated HEL peptides were evaluated for binding to major histocompatibility complex class II (MHC II) molecules and the immune response to those glycopeptides bound by MHC II molecules was then investigated. Immunization of mice with glycopeptides gave helper T-cells with specificity for the carbohydrate moiety.},
  author       = {Elofsson, Mikael},
  isbn         = {91-628-2103-2},
  keyword      = {HIV,immunogenic glycopeptides,T-cell,MHC,solid-phase glycopeptide synthesis,glycopeptides,glycoside synthesis,glycosylated amino acids,gp120,neoglycosphingolipids,Organic chemistry,Organisk kemi},
  language     = {eng},
  pages        = {94},
  publisher    = {Organic Chemistry, Lund University},
  title        = {Synthesis of glycosylated amino acids. Solid-phase assembly of T-cell immunogenic glycopeptides and fragments from HIV gp120},
  year         = {1996},
}