3KXD: Mthk rck

Crystal structure of the mthk rck in complex with cadmium. Determined by X-ray diffraction at 2.2 Å resolution. Released 21 Apr 2010.

Method: X-ray diffraction
Resolution: 2.2 Å
Organism: Methanothermobacter thermautotrophicus str. Delta H
Chains: 2
Atoms: 3,494
Mol. weight: 50.13 kDa
Ligands: CD
Released: 21 Apr 2010

Explore 3KXD in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

3KXD contains 26 α-helices and 26 β-strands across 2 chains. Residue ranges use author residue numbering, as in the PDB file, from PDBe. To see them in 3D, choose the Cartoon representation with Secondary structure coloring: helices, sheets and coils get different colors.

Chain A: 13 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	118-121	4	1
α-helix	125-133	9
β-strand	139-143	5	1
α-helix	146-148	3
α-helix	149-154	6
α-helix	157	1
β-strand	158-161	4	1
α-helix	167-172	6
β-strand	180-183	4	1
α-helix	188-201	14
β-strand	206-210	5	1
α-helix	214-216	3
α-helix	217-222	6
β-strand	227-229	3	1
α-helix	231-241	11
α-helix	247-256	10
β-strand	263-268	6	2
β-strand	273	1	3
β-strand	279	1	4
α-helix	280-283	4
α-helix	285-289	5
β-strand	292-298	7	2
β-strand	301-304	4	2
β-strand	311	1	4
β-strand	317-322	6	2
α-helix	324-334	11
β-strand	336	1	3

Chain B: 13 helices, 12 β-strands

Element	Residues	Length	Sheet
β-strand	118-121	4	5
α-helix	125-133	9
β-strand	139-143	5	5
α-helix	146-148	3
α-helix	149-154	6
β-strand	158-161	4	5
α-helix	167-172	6
β-strand	180-183	4	5
α-helix	188-201	14
β-strand	206-210	5	5
α-helix	214-216	3
α-helix	217-222	6
β-strand	227-229	3	5
α-helix	231-240	10
α-helix	247-255	9
β-strand	263-268	6	6
β-strand	279	1	7
α-helix	280-283	4
α-helix	285-289	5
α-helix	291	1
β-strand	292-298	7	6
β-strand	301-304	4	6
β-strand	311	1	7
β-strand	317-322	6	6
α-helix	324-333	10

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Calcium-gated potassium channel mthK	A, B	protein	224	Methanothermobacter thermautotrophicus str. Delta H	O27564 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>3KXD_1 Calcium-gated potassium channel mthK (chains A, B)
RHVVICGWSESTLECLRELRGSEVFVLAEDENVRKKVLRSGANFVHGDPTRVSDLEKANV
RGARAVIVDLESDSETIHCILGIRKIDESVRIIAEAERYENIEQLRMAGADQVISPFVIS
GRLMSRSIDDGYEAMFVQDVLAEESTRRMVEVPIPEGSKLEGVSVLDADIHDVTGVIIIG
VGRGDELIIDPPRDYSFRAGDIILGIGKPEEIERLKNYISALVP

Ligands and cofactors

ID	Name	Formula	Copies
CD	Cadmium ion	Cd	4

Primary citation

Structure of the MthK RCK in complex with cadmium. Dvir, H., Valera, E., Choe, S. J Struct Biol (2010) 171:231-237. DOI 10.1016/j.jsb.2010.03.020 · PubMed

Other PDB entries of the same protein (UniProt O27564 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3LDC 1.45 Å, High resolution open MthK pore structure crystallized in 100 mM K+
3LDD 1.45 Å, High resolution open MthK pore structure crystallized in 100 mM K+ and further soaked in…
6U9T 1.55 Å, Wild-type MthK pore in 50 mM K+
4HYO 1.65 Å, Crystal Structure of MthK Pore
6U9P 1.65 Å, Wild-type MthK pore in ~150 mM K+
2AEF 1.7 Å, Crystal Structures of the MthK RCK Domain in Ca2+ bound form
4HZ3 1.7 Å, MthK pore crystallized in presence of TBSb
3OUS 1.75 Å, MthK channel pore T59A mutant
3R65 1.8 Å, MthK channel pore E92Q mutant
6U9Y 1.8 Å, Wild-type MthK pore in 11 mM K+
4L74 1.84 Å, Ca2+-bound MthK RCK domain at 1.9 Angstrom with single ligand
6U9Z 1.95 Å, Wild-type MthK pore in 6 mM K+

Browse structure collections

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