PDBsum entry 3obt

Hydrolase

PDB id: 3obt

Contents

Protein chain

412 a.a.

Ligands

SLB

GOL ×11

Waters ×317

References listed in PDB file

Key reference

• Title: Botulinum neurotoxin serotype d attacks neurons via two carbohydrate-Binding sites in a ganglioside-Dependent manner.
• Authors: J.Strotmeier, K.Lee, A.K.Völker, S.Mahrhold, Y.Zong, J.Zeiser, J.Zhou, A.Pich, H.Bigalke, T.Binz, A.Rummel, R.Jin.
• Ref.: Biochem J, 2010, 431, 207-216.
• PubMed id: 20704566

Abstract

The extraordinarily high toxicity of botulinum neurotoxins primarily results from their specific binding and uptake into neurons. At motor neurons, the seven BoNT (botulinum neurotoxin) serotypes A-G inhibit acetylcholine release leading to flaccid paralysis. Uptake of BoNT/A, B, E, F and G requires a dual interaction with gangliosides and the synaptic vesicle proteins synaptotagmin or SV2 (synaptic vesicle glycoprotein 2), whereas little is known about the cell entry mechanisms of the serotypes C and D, which display the lowest amino acid sequence identity compared with the other five serotypes. In the present study we demonstrate that the neurotoxicity of BoNT/D depends on the presence of gangliosides by employing phrenic nerve hemidiaphragm preparations derived from mice expressing the gangliosides GM3, GM2, GM1 and GD1a, or only GM3 [a description of our use of ganglioside nomenclature is given in Svennerholm (1994) Prog. Brain Res. 101, XI-XIV]. High-resolution crystal structures of the 50 kDa cell-binding domain of BoNT/D alone and in complex with sialic acid, as well as biological analyses of single-site BoNT/D mutants identified two carbohydrate-binding sites. One site is located at a position previously identified in BoNT/A, B, E, F and G, but is lacking the conserved SXWY motif. The other site, co-ordinating one molecule of sialic acid, resembles the second ganglioside-binding pocket (the sialic-acid-binding site) of TeNT (tetanus neurotoxin).