title: N-terminal helix reorients in recombinant C-fragment of Clostridium botulinum type B.
abstract: Botulinum neurotoxins comprise seven distinct serotypes (A-G) produced by Clostridium botulinum. The crystal structure of the binding domain of the botulinum neurotoxin type B (BBHc) has been determined to 2A resolution. The overall structure of BBHc is well ordered and similar to that of the binding domain of the holotoxin. However, significant structural changes occur at what would be the interface of translocation and binding domains of the holotoxin. The loop 911-924 shows a maximum displacement of 14.8A at the farthest point. The N-terminal helix reorients and moves by 19.5A from its original position. BBHc is compared with the binding domain of the holotoxin of botulinum type A and B, and the tetanus C-fragment to characterize the heavy chain-carbohydrate interactions. The probable reasons for different binding affinity of botulinum and tetanus toxins are discussed.
authors.affiliation: Biology Department, Brookhaven National Laboratory, Upton, NY 11973, USA.
authors.forename: Seetharaman
authors.initials: S
authors.lastname: Jayaraman
authors.forename: Subramaniam
authors.initials: S
authors.lastname: Eswaramoorthy
authors.forename: S Ashraf
authors.initials: SA
authors.lastname: Ahmed
authors.forename: Leonard A
authors.initials: LA
authors.lastname: Smith
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Swaminathan
mesh_terms: D001905:Botulinum Toxins / Q000737:chemistry*; D019274:Botulinum Toxins, Type A; D002241:Carbohydrates / Q000737:chemistry; D003014:Clostridium botulinum / Q000737:chemistry*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D002241:Carbohydrates; D011994:Recombinant Proteins; C096323:rimabotulinumtoxinB; D001905:Botulinum Toxins; D019274:Botulinum Toxins, Type A