This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1kba
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:1kba.jpg|left|200px]] | [[Image:1kba.jpg|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_1kba", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | | | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), |
| - | | | + | or leave the SCENE parameter empty for the default display. |
| - | + | --> | |
| - | + | {{STRUCTURE_1kba| PDB=1kba | SCENE= }} | |
| - | + | ||
| - | + | ||
| - | }} | + | |
'''CRYSTAL STRUCTURE OF KAPPA-BUNGAROTOXIN AT 2.3-ANGSTROM RESOLUTION''' | '''CRYSTAL STRUCTURE OF KAPPA-BUNGAROTOXIN AT 2.3-ANGSTROM RESOLUTION''' | ||
| Line 28: | Line 25: | ||
[[Category: Grant, G A.]] | [[Category: Grant, G A.]] | ||
[[Category: Sacchettini, J C.]] | [[Category: Sacchettini, J C.]] | ||
| - | [[Category: | + | [[Category: Toxin]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 22:31:58 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 19:32, 2 May 2008
CRYSTAL STRUCTURE OF KAPPA-BUNGAROTOXIN AT 2.3-ANGSTROM RESOLUTION
Overview
kappa-Neurotoxins display a very low affinity for neuromuscular receptors, but bind tightly to, and inhibit, nicotinic acetylcholine receptors in neuronal tissue such as the chick ciliary ganglia. In contrast, alpha-neurotoxins bind with high affinity and inhibit nicotinic acetylcholine receptors at the neuromuscular junction. The origin of this difference in specificity has been a long-studied question in the field. Here we report the first crystal structure of a kappa-neurotoxin, kappa-bungarotoxin. Unlike the NMR structure previously reported [Sutcliffe, M. J., Dobson, C. M., & Oswald, R. E. (1992) Biochemistry 31, 2962-2970], the present crystal structure more accurately defines the polypeptide fold and the nature of the interaction between subunits in the active dimer, which is a unique feature of the kappa-neurotoxins. The structure has been refined to R = 19.6% with X-ray diffraction data extending to a resolution of 2.3 A. There are two independent protein molecules (66 amino acid residues each) in the asymmetric unit that are arranged as a dimer with the two subunits related by a rotation of 178.6 degrees. Each subunit consists of three main-chain loops. Three of the five beta-strands of each subunit form an antiparallel beta-sheet which becomes an extended six-stranded antiparallel beta-sheet, by virtue of the approximate 2-fold symmetry of the dimer. The interactions at the dimer interface consist of six main-chain-main-chain hydrogen bonds, as well as three other hydrogen-bonding interactions involving side chains.(ABSTRACT TRUNCATED AT 250 WORDS)
About this Structure
1KBA is a Single protein structure of sequence from Bungarus multicinctus. Full crystallographic information is available from OCA.
Reference
Crystal structure of kappa-bungarotoxin at 2.3-A resolution., Dewan JC, Grant GA, Sacchettini JC, Biochemistry. 1994 Nov 8;33(44):13147-54. PMID:7947721 Page seeded by OCA on Fri May 2 22:31:58 2008
