Importance of topology for glycocluster binding to Pseudomonas aeruginosa and Burkholderia ambifaria bacterial lectins

Abstract

Pseudomonas aeruginosa (PA) and Burkholderia ambifaria (BA) are two opportunistic Gram negative bacteria and major infectious agents involved in lung infection of cystic fibrosis patients. Both bacteria can develop resistance to conventional antibiotherapies. An alternative strategy consists of targeting virulence factors in particular lectins with high affinity ligands such as multivalent glycoclusters. LecA (PA-IL) and LecB (PA-IIL) are two tetravalent lectins from PA that recognise galactose and fucose respectively. BambL lectin from BA is trimeric with 2 binding sites per monomer and is also specific for fucose. These three lectins are potential therapeutic targets in an anti-adhesive anti-bacterial approach. Herein, we report the synthesis of 18 oligonucleotide pentofuranose-centered or mannitol-centered glycoclusters leading to tri-, penta- or decavalent clusters with different topologies. The linker arm length between the core and the carbohydrate epitope was also varied leading to 9 galactoclusters targeting LecA and 9 fucoclusters targeting both LecB and BambL. Their dissociation constants (Kd) were determined using a DNA-based carbohydrate microarray technology. The trivalent xylo-centered galactocluster and the ribo-centered fucocluster exhibited the best affinity for LecA and LecB respectively while the mannitol-centered decafucocluster displayed the best affinity to BambL. These data demonstrated that the topology and nature of linkers were the predominant factors for achieving high affinity rather than valency.

Therapeutic Antibodies to Ganglioside GD2 Evolved from Highly Selective Germline Antibodies

“…Of particular relevance to this study, many of the array components contain glycan sequences that are closely related to GD2 such as GD1a, GD1b, GD3, GM1a, GM1b, GM2, GM3, GT1a, GT2, GT3, GQ2, and GA2 (Figure 1). We (Gildersleeve et al, 2008; Gildersleeve and Wright, 2016; Oyelaran et al, 2009; Shoreibah et al, 2011; Zhang et al, 2010) and others (Chang et al, 2010; Dupin et al, 2015; Godula and Bertozzi, 2012; Goudot et al, 2013; Hung et al, 2013; Jaipuri et al, 2008; Karamanska et al, 2008; Ligeour et al, 2015; Park and Shin, 2007; Shivatare et al, 2013; Song et al, 2008; Wang et al, 2008) have used glycan microarrays to evaluate apparent K D values for carbohydrate-protein interactions and have found good agreement with previously published values measured by surface plasmon resonance.…”

Cyclotriveratrylene‐Based Glycoclusters as High Affinity Ligands of Bacterial Lectins from Pseudomonas aeruginosa and Burkholderia ambifaria

“…The six fucose binding sites of BambL were expected to interact each with one epitope from the hexavalent CTV‐based glycocluster 10‐Fuc 6 but the stoichiometry (N) of 0.273 indicates that the simultaneous interaction of six residues could not be reached probably for geometrical reasons. The affinity observed is encouraging when compared to previous high affinity ligands previously reported …”

Toward the Rational Design of Galactosylated Glycoclusters That Target Pseudomonas aeruginosa Lectin A (LecA): Influence of Linker Arms That Lead to Low‐Nanomolar Multivalent Ligands

“…[33][34][35][36][37] Oligonucleotide chemistry with the powerful phosphoramidite coupling offers ag eneral and accessiblep latform for the designo fm ultivalent glycoclusters because valency can be easily modulated as well as the overall geometry of the macromolecule with optimalw ater solubility thanks to the phosphodiester groups. [14,[38][39][40][41][42][43][44] In this context, at etravalent mannopyranoside core platform was also introduced and provided glycoclustersofh igh affinity toward LecA as antibacterial candidates. [14,43,45,46] The typeo flinker used to connectt he carbohydratet ot he core also greatly affects the binding properties towardl ectins.…”