PDBsum entry 4jtc

Transport protein/toxin

PDB id: 4jtc

Contents

Protein chains

326 a.a.

386 a.a.

363 a.a.

37 a.a.

Ligands

NAP ×2

PGW ×17

Metals

_CS ×8

PDB id:

4jtc

Name:

Transport protein/toxin

Title:

Crystal structure of kv1.2-2.1 paddle chimera channel in complex with charybdotoxin in cs+

Structure:

Voltage-gated potassium channel subunit beta-2. Chain: a, g. Synonym: k(+) channel subunit beta-2, kv-beta-2. Engineered: yes. Potassium voltage-gated channel subfamily a member 2, potassium voltage-gated channel subfamily b member 1. Chain: b, h. Synonym: rak, rbk2, rck5, voltage-gated potassium channel subunit kv1.2, delayed rectifier potassium channel 1, drk1, voltage-gated

Source:

Rattus norvegicus. Brown rat,rat,rats. Organism_taxid: 10116. Gene: ckbeta2, kcnab2, kcnb3. Expressed in: pichia pastoris. Expression_system_taxid: 4922. Gene: kcna2, kcnb1. Leiurus quinquestriatus hebraeus. Yellow scorpion.

Resolution:

2.56Å R-factor: 0.237 R-free: 0.262

Authors:

A.Banerjee,A.Lee,E.Campbell,R.Mackinnon

Key ref:

A.Banerjee et al. (2013). Structure of a pore-blocking toxin in complex with a eukaryotic voltage-dependent K(+) channel. Elife, 2, e00594. PubMed id: 23705070 DOI: 10.7554/eLife.00594

Date:

23-Mar-13 Release date: 12-Jun-13

Protein chains

P62483  (KCAB2_RAT) -  Voltage-gated potassium channel subunit beta-2 from Rattus norvegicus

Seq: 367 a.a.

Struc: 326 a.a.

Protein chain

P15387  (KCNB1_RAT) -  Potassium voltage-gated channel subfamily B member 1 from Rattus norvegicus

Seq: 857 a.a.

Struc: 386 a.a.*

Protein chain

P63142  (KCNA2_RAT) -  Potassium voltage-gated channel subfamily A member 2 from Rattus norvegicus

Seq: 499 a.a.

Struc: 386 a.a.*

Protein chain

P15387  (KCNB1_RAT) -  Potassium voltage-gated channel subfamily B member 1 from Rattus norvegicus

Seq: 857 a.a.

Struc: 363 a.a.*

Protein chain

P63142  (KCNA2_RAT) -  Potassium voltage-gated channel subfamily A member 2 from Rattus norvegicus

Seq: 499 a.a.

Struc: 363 a.a.*

Protein chain

P13487  (KAX11_LEIHE) -  Potassium channel toxin alpha-KTx 1.1 from Leiurus hebraeus

Seq: 59 a.a.

Struc: 37 a.a.*

* PDB and UniProt seqs differ at 423 residue positions (black crosses)

Enzyme reactions

• Enzyme class: Chains A, G: E.C.1.1.1.- - ?????

DOI no: 10.7554/eLife.00594

Elife 2:e00594 (2013)

PubMed id: 23705070

Structure of a pore-blocking toxin in complex with a eukaryotic voltage-dependent K(+) channel.

A.Banerjee, A.Lee, E.Campbell, R.Mackinnon.

ABSTRACT

Pore-blocking toxins inhibit voltage-dependent K(+) channels (Kv channels) by plugging the ion-conduction pathway. We have solved the crystal structure of paddle chimera, a Kv channel in complex with charybdotoxin (CTX), a pore-blocking toxin. The toxin binds to the extracellular pore entryway without producing discernable alteration of the selectivity filter structure and is oriented to project its Lys27 into the pore. The most extracellular K(+) binding site (S1) is devoid of K(+) electron-density when wild-type CTX is bound, but K(+) density is present to some extent in a Lys27Met mutant. In crystals with Cs(+) replacing K(+), S1 electron-density is present even in the presence of Lys27, a finding compatible with the differential effects of Cs(+) vs K(+) on CTX affinity for the channel. Together, these results show that CTX binds to a K(+) channel in a lock and key manner and interacts directly with conducting ions inside the selectivity filter. DOI:http://dx.doi.org/10.7554/eLife.00594.001.