Inhibitory Effect of Multivalent Rhamnobiosides on Recombinant Horseshoe Crab Plasma Lectin Interactions with Pseudomonas aeruginosa PAO1

Abstract

To evaluate the molecular interaction of recombinant horseshoe crab plasma lectin (rHPL) with Pseudomonas aeruginosa PAO1, multivalent rhamnobioside derivatives were designed. Eight rhamnoclusters with three or four α(1-3)-rhamnobiosides attached to different central cores, such as methyl gallate, pentaerythritol, and N-Boc Tris, through either an ethylene glycol or a tetraethylene glycol linker, were assembled in two consecutive azide-alkyne cycloaddition click reactions. The synthetic method embraced the preparation of two α(1-3)-rhamnobiosides with different linker arms and their conjugation, in stoichiometric or substoichiometric amounts, to propargyl ether-functionalized tri- or tetravalent scaffolds. A divalent derivative and two self-assembling rhamnobiosides were also prepared. The different architectures and valences of the rhamnoclusters provided an opportunity to evaluate the impact of topology and valency on the binding properties toward rHPL. Inhibitory ELISA data showed that all covalently linked rhamnoclusters could inhibit P. aeruginosa PAO1 recognition activity of rHPL with high efficacy. Trivalent rhamnobiosides showed a stronger inhibitory effect on P. aeruginosa PAO1 binding, and the more flexible clusters on a pentaerythritol or a Tris core were superior to the less flexible methyl gallate-based clusters. Interestingly, the length of the linker arms had a very low impact on the binding ability of the rhamnoclusters. Herein, the two trivalent derivatives on an N-Boc protected Tris central core were the best inhibitors. The self-assembling amphiphilic rhamnobioside derivatives were found to display no multivalent effect.

Multifunctional Glycoconjugates for Recruiting Natural Antibodies against Cancer Cells

“…Therefore, we decided to synthesized tetra‐ and hexadecavalent Rha‐based ABMs (Scheme ) by using peptide carriers previously identified as well‐suited scaffolds for multivalent presentation of sugars . Starting from the tetraazido cyclodecapeptide 1 , a first CuAAC reaction with propargyl l ‐rhamnopyranoside afforded the tetravalent cluster 2 . On one hand, the introduction of azidoacetic acid on the remaining free lysine residue led to the tetravalent ABM 3 .…”

“… Synthesis of tetra‐ and hexadecavalent rhamnosylated ABMs. Reagents and conditions: i) Propargyl α‐ l ‐rhamnopyranoside, CuSO 4 ⋅ 5 H 2 O, tris(3‐hydroxypropyltriazolylmethyl)amine (THPTA), NaAsc, DMF/phosphate‐buffered saline (PBS), RT, 1 h; ii) azidoacetic or pentynoic acid succinimide ester, diisopropylethylamine (DIPEA), DMF, RT, 1 h (see the Supporting Information).…”

“…Therefore, we decided to synthesized tetra-and hexadecavalent Rha-basedA BMs (Scheme 1) by using peptidec arriers previouslyi dentified as well-suited scaffolds form ultivalent presentation of sugars. [18,19] Startingf rom the tetraazidoc yclodecapeptide 1, [20] af irst CuAAC reactionw ith propargyl l-rhamnopyranoside [21] afforded the tetravalent cluster 2.O no ne hand, the introduction of azidoacetic acid on the remaining free lysine residue led to the tetravalent ABM 3.O nt he other hand, functionalization of this lysine with pentynoic acid allowed for as econd CuAAC reaction. Intermediate 4 was reacted with 1,y ieldingd endrimer 5.…”

“…Ta rgeted therapy aims at delivering drugs in tumor cells by using selective ligands of receptors present at their surface. [24] We selected aw ell-known cyclopeptidec ontaining the triad sequence Arg-Gly-Asp( cRGD), which is one of the most potent ligand for the a v b 3 integrins that are overexpressed in tumor Scheme1.Synthesis of tetra-and hexadecavalent rhamnosylatedA BMs.R eagents and conditions: i) Propargyl a-l-rhamnopyranoside, [21] CuSO 4 ·5H 2 O, tris(3hydroxypropyltriazolylmethyl)amine (THPTA),N aAsc, DMF/phosphate-buffered saline( PBS), RT,1h; ii)azidoacetic [22] or pentynoic acid succinimide ester, [23] diisopropylethylamine (DIPEA), DMF, RT,1h(seethe SupportingInformation).…”

Synthesis of α‐l‐Fucopyranoside‐Presenting Glycoclusters and Investigation of Their Interaction with Photorhabdus asymbiotica Lectin (PHL)

“…Synthesis Similar to our recent works, [6,7] propargylatedm ethyl gallate 1 [8] and pentaerythritol 2 [9] were chosen as multivalent scaffolds, whereas heterobifunctionalized tetraethylene glycol 3 [10] and ethylene glycol 4 [11] were used as linkers with different lengths. Based on the known X-ray structure of PHL, the average distances between the fucose-binding sites is approximately 19 ,s ot hese linkers are long enough that the a-lfucose units of the fucoclusters are able to bind to more than one bindingp ocket of the lectin . We efficiently prepared propargyl a-l-fucoside 5 by Fischer glycosylation using sulfamic acid [12] and utilized it in both unprotected and acetylated form 6 [13] to create multivalent structures ( Figure 1).…”