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A highly convergent synthesis of the sialic acid-rich biantennary N-linked glycan found in human glycoprotein hormones and its utility in preparing a fragment derived from the [beta]-domain of human Follicle-Stimulating Hormone (hFSH) are described. The synthetic glycan is used for preparing the glycosylated 20-27aa domain of the [beta]-subunit of hFSH under a Lansbury aspartylation protocol and it has provided protected [beta]-hFSH subunit functionalized with chitobiose at positions 7 and 24.

Critical to the search for an effective HIV-1 vaccine is the development of immunogens capable of inducing broadly neutralizing antibodies (BnAbs). A key first step in this process is to design immunogens that can be recognized by known BnAbs. The monoclonal antibody PG9 is a BnAb that neutralizes diverse strains of HIV-1 by targeting a conserved carbohydrate-protein epitope in the variable 1 and 2 (V1V2) region of the viral envelope. Important for recognition are two closely spaced N-glycans at Asn160 and Asn156. Glycopeptides containing this synthetically challenging bis-N-glycosylated motif were prepared by convergent assembly, and were shown to be antigenic for PG9. Synthetic glycopeptides such as these may be useful for the development of HIV-1 vaccines based on the envelope V1V2 BnAb epitope. [ABSTRACT FROM AUTHOR]

Described herein is the first total chemical synthesis of the unique α-subunit of the human glycoprotein hormone (α-hGPH). Unlike the biologically derived glycoprotein hormones, which are isolated as highly complex mixtures of glycoforms, α-hGPH obtained by chemical synthesis contains discrete homogeneous glycoforms. Two such systems have been prepared. One contains the disaccharide chitobiose at the natural N-glycosylation sites. The other contains dodecamer oligosaccharides at these same sites. The dodecamer sugar is a consensus sequence incorporating the key features associated with human glycoproteins. [ABSTRACT FROM AUTHOR]

We have designed a mass stable reporter (msr) tag with m/z over 500, trifluoroacetyl(α,α-diethyl)Gly-Lys(Nϵbiotin)-(D)Lys-Cys, for the quantification of the uptake and study of the degradation processes of cell-penetrating peptides (CPP), by matrix assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. This tag was found stable in cell lysis conditions. Using a quantitative MALDI-TOF mass spectrometry analysis based method, an accurate tracking of a new CPP and of its degradation products could be done. (1) The new msr(W/R) nonapeptide (H-RRWWRRWRR-NH2) enters chinese hamster ovary (CHO) K1 cells with a kinetic reaching a steady state after 30-60 min of incubation. This plateau was stable for 4 h and decreased slowly afterward. (2) The peptide msr(W/R) nonapeptide was not cytotoxic over 48 h incubation with CHO cells. (3) After 1 h incubation, the msr(W/R) nonapeptide accumulated with a 3-fold higher concentration than the extracellularly added concentration (7.5 µM). (4) The intracellular quantification was accurate with less than 3% of the quantified peptide being potentially membrane-bound. (5) There was no leakage of the full-length CPP outside the cells. And, finally, (6) analysis of the degradation process of this new CPP suggests that the peptide did not traffick to lysosomes. [ABSTRACT FROM AUTHOR]

A highly convergent synthesis of the sialic acid-rich biantennary N-linked glycan found in human glycoprotein hormones and its use in the synthesis of a fragment derived from the β-domain of human Follicle-Stimulating Hormone (hFSH) are described. The synthesis highlights the use of the Sinaÿ radical glycosidation protocol for the simultaneous installation of both biantennary side-chains of the dodecasaccharide as well as the use of glycal chemistry to construct the tetrasaccharide core in an efficient manner. The synthetic glycan was used to prepare the glycosylated 20-27aa domain of the β-subunit of hFSH under a Lansbury aspartylation protocol. The proposed strategy for incorporating the prepared N-linked dodecasaccharide-containing 20-27aa domain into β-hFSH subunit was validated in the context of a model system, providing protected β-hFSH subunit functionalized with chitobiose at positions 7 and 24. [ABSTRACT FROM AUTHOR]