PDBsum entry 1bkt

Neurotoxin

PDB id: 1bkt

Contents

Protein chain

38 a.a. *

* Residue conservation analysis

PDB id:

1bkt

Name:

Neurotoxin

Title:

Bmktx toxin from scorpion buthus martensii karsch, nmr, 25 structures

Structure:

Bmktx. Chain: a. Engineered: yes

Source:

Mesobuthus martensii. Chinese scorpion. Organism_taxid: 34649. Strain: karsch

NMR struc:

25 models

Authors:

J.G.Renisio,R.Romi-Lebrun,E.Blanc,O.Bornet,T.Nakajima,H.Darbon

Key ref:

J.G.Renisio et al. (2000). Solution structure of BmKTX, a K+ blocker toxin from the Chinese scorpion Buthus Martensi. Proteins, 38, 70-78. PubMed id: 10651040 DOI: 10.1002/(SICI)1097-0134(20000101)38:1<70::AID-PROT8>3.0.CO;2-5

Date:

03-Jul-98 Release date: 13-Jan-99

Protein chain

Q9NII7  (KAX36_MESMA) -  Potassium channel toxin alpha-KTx 3.6 from Mesobuthus martensii

Seq: 60 a.a.

Struc: 38 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

DOI no: 10.1002/(SICI)1097-0134(20000101)38:1<70::AID-PROT8>3.0.CO;2-5

Proteins 38:70-78 (2000)

PubMed id: 10651040

Solution structure of BmKTX, a K+ blocker toxin from the Chinese scorpion Buthus Martensi.

J.G.Renisio, R.Romi-Lebrun, E.Blanc, O.Bornet, T.Nakajima, H.Darbon.

ABSTRACT

BmKTX is a toxin recently purified from the venom of Buthus Martensi, which belongs to the kaliotoxin family. We have determined its solution structure by use of conventional two-dimensional NMR techniques followed by distance-geometry and energy minimization. The calculated structure is composed of a short alpha-helix (residues 14 to 20) connected by a tight turn to a two-stranded antiparallel beta-sheet (sequences 25-27 and 32-34). The beta-turn connecting these strands belongs to type I. The N-terminal segment (sequence 1 to 8) runs parallel to the beta-sheet although it cannot be considered as a third strand. Comparison of the conformation of BmKTX and toxins of the kaliotoxin family clearly demonstrates that they are highly related. Therefore, analysis of the residues belonging to the interacting surface of those toxins allows us to propose a functional map of BmKTX slightly different from the one of KTX and AgTX2, which may explain the variations in affinities of these toxins towards the Kv1.3 channels.

Selected figure(s)

Figure 5.
Figure 5. The toxin functional maps. The structures on the left, middle, and right correspond to KTX, BmKTX, and AgTX2 respectively. The residues crucial for toxins to interact with the Kv1.3 channel are in red. Influential residues are in blue and additional residues are in pink. Histidine H9, the residue that determines the specificity of BmKTX interaction with the Kv1.3 channel, is in green.

Figure 6.
Figure 6. Docking of BmKTX on a model of Kv1.3. The channel backbone is in yellow and its interacting side chains in orange. BmKTX backbone is in gray and its interacting side chains are in red for crucial residues, in blue for influential residues, and in pink for additional residues. Highlighted histidine H9 is in green.

The above figures are reprinted by permission from John Wiley & Sons, Inc.: Proteins (2000, 38, 70-78) copyright 2000.

Figures were selected by an automated process.