3RMY

Crystal structure of HCR/D W1238A mutant

Summary for 3RMY

• Entry DOI: 10.2210/pdb3rmy/pdb
• Related: 3N7J 3RMX
• Descriptor: Botulinum neurotoxin type D, GLYCEROL (3 entities in total)
• Functional Keywords: botulinum neurotoxin, ganglioside binding loop, w1238a, toxin
• Biological source: Clostridium botulinum
• Cellular location: Botulinum neurotoxin D light chain: Secreted. Botulinum neurotoxin D heavy chain: Secreted: P19321
• Total number of polymer chains: 4
• Total formula weight: 192764.77

Authors

Fu, Z.,Karalewitz, A.,Kroken, A.,Kim, J.-J.P.,Barbieri, J.T. (deposition date: 2011-04-21, release date: 2011-06-01, Last modification date: 2024-10-30)

Primary citation

Kroken, A.R.,Karalewitz, A.P.,Fu, Z.,Kim, J.J.,Barbieri, J.T.
Novel Ganglioside-mediated Entry of Botulinum Neurotoxin Serotype D into Neurons.
J.Biol.Chem., 286:26828-26837, 2011

PubMed Abstract: Botulinum Neurotoxins (BoNTs) are organized into seven serotypes, A-G. Although several BoNT serotypes enter neurons through synaptic vesicle cycling utilizing dual receptors (a ganglioside and a synaptic vesicle-associated protein), the entry pathway of BoNT/D is less well understood. Although BoNT/D entry is ganglioside-dependent, alignment and structural studies show that BoNT/D lacks key residues within a conserved ganglioside binding pocket that are present in BoNT serotypes A, B, E, F, and G, which indicate that BoNT/D-ganglioside interactions may be unique. In this study BoNT/D is shown to have a unique association with ganglioside relative to the other BoNT serotypes, utilizing a ganglioside binding loop (GBL, residues Tyr-1235-Ala-1245) within the receptor binding domain of BoNT/D (HCR/D) via b-series gangliosides, including GT1b, GD1b, and GD2. HCR/D bound gangliosides and entered neurons dependent upon the aromatic ring of Phe-1240 within the GBL. This is the first BoNT-ganglioside interaction that is mediated by a phenylalanine. In contrast, Trp-1238, located near the N terminus of the ganglioside binding loop, was mostly solvent-inaccessible and appeared to contribute to maintaining the loop structure. BoNT/D entry and intoxication were enhanced by membrane depolarization via synaptic vesicle cycling, where HCR/D colocalized with synaptophysin, a synaptic vesicle marker, but immunoprecipitation experiments did not detect direct association with synaptic vesicle protein 2. Thus, BoNT/D utilizes unique associations with gangliosides and synaptic vesicles to enter neurons, which may facilitate new neurotoxin therapies.

PubMed: 21632541
DOI: 10.1074/jbc.M111.254086

Experimental method

X-RAY DIFFRACTION (2.3 Å)