2HTK: H/Cl exchange transporter clcA

Structure of the Escherichia coli ClC chloride channel Y445A mutant and Fab complex. Determined by X-ray diffraction at 3.41 Å resolution. Released 19 Sept 2006.

Method: X-ray diffraction
Resolution: 3.41 Å
Organisms: Escherichia coli, Mus musculus
Chains: 6
Atoms: 13,211
Mol. weight: 194.32 kDa
Released: 19 Sept 2006

Explore 2HTK in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

2HTK contains 74 α-helices and 91 β-strands across 6 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: 24 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	18-26	9
α-helix	33-70	38
α-helix	75-100	26
α-helix	102-104	3
α-helix	109-116	8
α-helix	124-140	17
β-strand	146	1	1
α-helix	148-165	18
α-helix	171-189	19
α-helix	193-199	7
α-helix	200-204	5
α-helix	215-232	18
α-helix	249-251	3
α-helix	253-284	32
α-helix	288-308	21
α-helix	319-324	6
α-helix	330-348	19
β-strand	355	1	1
α-helix	357-378	22
α-helix	380-382	3
α-helix	386-392	7
α-helix	398-402	5
α-helix	405-415	11
α-helix	419-421	3
α-helix	422-438	17
α-helix	444-458	15

Chain B: 23 helices, 2 β-strands

Element	Residues	Length	Sheet
α-helix	19-25	7
α-helix	33-70	38
α-helix	75-100	26
α-helix	102-104	3
α-helix	109-116	8
α-helix	124-140	17
β-strand	146	1	2
α-helix	148-166	19
α-helix	171-190	20
α-helix	193-199	7
α-helix	200-204	5
α-helix	215-233	19
α-helix	249-251	3
α-helix	252-284	33
α-helix	288-308	21
α-helix	319-324	6
α-helix	330-349	20
β-strand	355	1	2
α-helix	357-378	22
α-helix	386-394	9
α-helix	396-400	5
α-helix	405-416	12
α-helix	419-421	3
α-helix	422-437	16
α-helix	444-454	11

Chain C: 6 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	3-7	5	3
β-strand	10-12	3	4
β-strand	17-25	9	3
β-strand	34-39	6	4
β-strand	45-51	7	4
β-strand	58-60	3	4
β-strand	68-73	6	3
β-strand	78-84	7	3
α-helix	88-90	3
β-strand	92-101	10	4
β-strand	106-111	6	4
β-strand	115-119	5	4
α-helix	122-124	3
β-strand	125	1	5
β-strand	128-131	4	6
α-helix	133-135	3
β-strand	143-145	3	7
β-strand	148-153	6	6
β-strand	154	1	5
β-strand	159-162	4	8
α-helix	163-165	3
β-strand	171-173	3	6
α-helix	174-176	3
β-strand	177-179	3	6
β-strand	182-189	8	6
β-strand	190-192	3	7
β-strand	202-207	6	8
α-helix	208-210	3
β-strand	212-217	6	8

Chain D: 8 helices, 20 β-strands

Element	Residues	Length	Sheet
β-strand	4-5	2	9
β-strand	10-13	4	10
β-strand	19-29	11	9
β-strand	33-37	5	10
β-strand	44-48	5	10
α-helix	49-51	3
β-strand	52-53	2	10
α-helix	54	1
β-strand	61-74	14	9
α-helix	79-81	3
β-strand	83-89	7	10
α-helix	95	1
β-strand	96-97	2	10
β-strand	101-105	5	10
β-strand	110	1	11
β-strand	113-117	5	12
α-helix	118-120	3
α-helix	121-124	4
β-strand	128-138	11	12
β-strand	139	1	11
β-strand	143-149	7	13
β-strand	152-154	3	13
β-strand	158-162	5	12
α-helix	163-166	4
β-strand	172-181	10	12
α-helix	182-186	5
β-strand	190-197	8	13
β-strand	204-209	6	13

Chain E: 6 helices, 23 β-strands

Element	Residues	Length	Sheet
β-strand	3-7	5	14
β-strand	11-12	2	15
β-strand	17-25	9	14
β-strand	34-39	6	16
β-strand	45-51	7	16
β-strand	58-60	3	16
β-strand	68-73	6	14
β-strand	78-84	7	14
α-helix	88-90	3
β-strand	92-101	10	16
β-strand	106-111	6	16
β-strand	115-117	3	16
β-strand	118-119	2	15
β-strand	125	1	17
α-helix	126-127	2
β-strand	128-132	5	18
α-helix	133-135	3
β-strand	143-153	11	18
β-strand	154	1	17
β-strand	159-162	4	19
α-helix	163-165	3
β-strand	167	1	19
β-strand	171-173	3	18
α-helix	174-176	3
β-strand	177-178	2	18
β-strand	183-192	10	18
β-strand	202-207	6	19
β-strand	212-217	6	19
α-helix	219-221	3

Chain F: 7 helices, 21 β-strands

Element	Residues	Length	Sheet
β-strand	4-6	3	20
β-strand	10-13	4	21
β-strand	19-29	11	20
β-strand	33-37	5	21
β-strand	44-45	2	21
β-strand	47-48	2	22
β-strand	52-53	2	22
α-helix	54	1
β-strand	61-74	14	20
α-helix	79-81	3
β-strand	84-89	6	21
α-helix	95	1
β-strand	96-97	2	21
β-strand	101-105	5	21
β-strand	110	1	23
β-strand	113-117	5	24
α-helix	118-120	3
α-helix	121-124	4
β-strand	128-138	11	24
β-strand	139	1	23
β-strand	143-149	7	25
β-strand	152-154	3	25
β-strand	158-162	5	24
α-helix	163-166	4
β-strand	172-181	10	24
α-helix	182-186	5
β-strand	190-197	8	25
β-strand	200-209	10	25

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
H(+)/Cl(-) exchange transporter clcA	A, B	protein	473	Escherichia coli	P37019 (AlphaFold model)
Fab fragment, Heavy chain	C, E	protein	221	Mus musculus	P01808 (AlphaFold model)
Fab fragment, Light chain	D, F	protein	211	Mus musculus	P01837 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>2HTK_1 H(+)/Cl(-) exchange transporter clcA (chains A, B)
MKTDTPSLETPQAARLRRRQLIRQLLERDKTPLAILFMAAVVGTLVGLAAVAFDKGVAWL
QNQRMGALVHTADNYPLLLTVAFLCSAVLAMFGYFLVRKYAPEAGGSGIPEIEGALEDQR
PVRWWRVLPVKFFGGLGTLGGGMVLGREGPTVQIGGNIGRMVLDIFRLKGDEARHTLLAT
GAAAGLAAAFNAPLAGILFIIEEMRPQFRYTLISIKAVFIGVIMSTIMYRIFNHEVALID
VGKLSDAPLNTLWLYLILGIIFGIFGPIFNKWVLGMQDLLHRVHGGNITKWVLMGGAIGG
LCGLLGFVAPATSGGGFNLIPIATAGNFSMGMLVFIFVARVITTLLCFSSGAPGGIFAPM
LALGTVLGTAFGMVAVELFPQYHLEAGTFAIAGMGALLAASIRAPLTGIILVLEMTDNYQ
LILPMIITGLGATLLAQFTGGKPLASAILARTLAKQEAEQLARSKAASASENT

Sequence of entity 2 (C, E), FASTA

>2HTK_2 Fab fragment, Heavy chain (chains C, E)
VRLLESGGGLVQPGGSLKLSCAASGFDYSRYWMSWVRQAPGKGLKWIGEINPVSSTINYT
PSLKDKFIISRDNAKDTLYLQISKVRSEDTALYYCARLYYGYGYWYFDVWGAGTTVTVSS
AKTTPPSVYPLAPGSAAAAASMVTLGCLVKGYFPEPVTVTWNSGSLAAGVHTFPAVLQAA
LYTLSSSVTVPSSSWPSETVTCNVAHPASSTKVDKKIVPRA

Sequence of entity 3 (D, F), FASTA

>2HTK_3 Fab fragment, Light chain (chains D, F)
DIVLTQSPAIMSAAPGDKVTMTCSASSSVSYIHWYQQKSGTSPKRWIYDTSKLTSGVPVR
FSGSGSGTSYSLTINTMEAEDAATYYCQQWSSHPQTFGGGTKLEILRADAAPTVSIFPPS
SEQLTSGGASVVCFLNNFYPKDINVKWKIDGSERQNGVLNSWTDQDSKDSTYSMSSTLTL
TKDEYERHNSYTCEATHKTSTSPIVKSFNRA

Primary citation

Synergism between halide binding and proton transport in a CLC-type exchanger. Accardi, A., Lobet, S., Williams, C. et al. J Mol Biol (2006) 362:691-699. DOI 10.1016/j.jmb.2006.07.081 · PubMed

Other PDB entries of the same protein (UniProt P37019 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4ENE 2.4 Å, Structure of the N- and C-terminal trimmed ClC-ec1 Cl-/H+ antiporter and Fab Complex
1OTS 2.51 Å, Structure of the Escherichia coli ClC Chloride channel and Fab Complex
8GA1 2.6 Å, CLC-ec1 R230C/L249C/C85A at pH 4.5 100mM Cl Swap
8GA5 2.6 Å, CLC-ec1 L25C/A450C/C85A at pH 4.5 100mM Cl Intermediate
6V2J 2.62 Å, Crystal structure of ClC-ec1 triple mutant (E113Q, E148Q, E203Q)
6ADB 2.69 Å, Crystal structure of the E148N mutant CLC-ec1 in 20mM bromide
3DET 2.8 Å, Structure of the E148A, Y445A doubly ungated mutant of E.coli CLC_Ec1, Cl-/H+ antiporter
4KKL 2.85 Å, Structure of the E148A mutant of CLC-ec1 delta NC construct in 100mM fluoride
4KK8 2.86 Å, Structure of the E148Q mutant of CLC-ec1 deltaNC construct in 100mM fluoride
4KJQ 2.88 Å, Structure of the CLC-ec1 deltaNC construct in 100mM fluoride
3EJZ 2.9 Å, Structure of E203V mutant E.coli Cl-/H+ exchanger, CLC-ec1
7CVT 2.9 Å, Crystal structure of the C85A/L194A/H234C mutant CLC-ec1 with Fab fragment

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