1Q1B: E. coli MalK in the nucleotide-free form

Crystal structure of E. coli MalK in the nucleotide-free form. Determined by X-ray diffraction at 2.8 Å resolution. Released 30 Sept 2003.

Method: X-ray diffraction
Resolution: 2.8 Å
Organism: Escherichia coli
Chains: 4
Atoms: 11,412
Mol. weight: 168.97 kDa
Released: 30 Sept 2003

Explore 1Q1B in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

1Q1B contains 54 α-helices and 108 β-strands across 4 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, 27 β-strands

Element	Residues	Length	Sheet
β-strand	5-8	4	1
β-strand	9-13	5	2
β-strand	16-22	7	2
β-strand	25	1	1
α-helix	26-27	2
β-strand	31-35	5	3
α-helix	42-50	9
β-strand	57-62	6	1
β-strand	65-66	2	1
α-helix	72-74	3
β-strand	77-81	5	3
α-helix	106-120	15
α-helix	124-126	3
α-helix	136-150	15
β-strand	154-158	5	3
α-helix	169-182	14
β-strand	186-190	5	3
α-helix	194-200	7
β-strand	203-208	6	3
β-strand	211-216	6	3
α-helix	218-223	6
β-strand	227	1	4
α-helix	228-233	6
β-strand	240-248	9	5
β-strand	255-257	3	5
α-helix	261-263	3
β-strand	265-267	3	5
β-strand	270	1	6
β-strand	280-285	6	5
α-helix	287-289	3
β-strand	291	1	7
β-strand	299-309	11	7
β-strand	313-320	8	7
β-strand	323-332	10	7
β-strand	342-346	5	7
α-helix	349-351	3
β-strand	353-355	3	5
β-strand	360	1	4
β-strand	361	1	5
β-strand	364	1	6

Chain B: 12 helices, 28 β-strands

Element	Residues	Length	Sheet
β-strand	5	1	8
β-strand	6-7	2	9
β-strand	9-11	3	10
β-strand	19-22	4	10
β-strand	25	1	8
β-strand	31-35	5	11
α-helix	38-40	3
α-helix	42-49	8
β-strand	59-60	2	9
β-strand	77	1	12
α-helix	92-94	3
α-helix	144-147	4
β-strand	154	1	12
α-helix	172-182	11
β-strand	186	1	12
β-strand	187-190	4	11
α-helix	194-200	7
β-strand	203-208	6	11
β-strand	211-216	6	11
α-helix	218-223	6
β-strand	227	1	13
α-helix	228-233	6
α-helix	238-239	2
β-strand	240-248	9	14
β-strand	255-257	3	14
α-helix	261-263	3
β-strand	265-267	3	14
β-strand	270	1	15
β-strand	280-285	6	14
α-helix	287-289	3
β-strand	291	1	16
β-strand	299-309	11	16
β-strand	313-320	8	16
β-strand	323-332	10	16
β-strand	342-346	5	16
β-strand	353-355	3	14
β-strand	360	1	13
β-strand	361	1	14
β-strand	364	1	15
α-helix	367-369	3

Chain C: 14 helices, 27 β-strands

Element	Residues	Length	Sheet
β-strand	5-10	6	17
β-strand	12	1	18
β-strand	17	1	18
β-strand	22-25	4	17
β-strand	31-35	5	19
α-helix	38-40	3
α-helix	42-50	9
β-strand	57-61	5	17
β-strand	66	1	17
α-helix	72-74	3
β-strand	77-81	5	19
α-helix	106-120	15
α-helix	124-126	3
α-helix	131-133	3
α-helix	136-148	13
β-strand	154-158	5	19
α-helix	166-182	17
β-strand	186-190	5	19
α-helix	194-200	7
β-strand	203-208	6	19
β-strand	211-216	6	19
α-helix	218-223	6
β-strand	227	1	20
α-helix	228-233	6
α-helix	238-239	2
β-strand	240-248	9	21
β-strand	255-257	3	21
β-strand	265-267	3	21
β-strand	270	1	22
β-strand	280-285	6	21
α-helix	287-289	3
β-strand	291	1	23
β-strand	299-309	11	23
β-strand	313-320	8	23
β-strand	323-332	10	23
β-strand	342-346	5	23
α-helix	349-351	3
β-strand	353-355	3	21
β-strand	360	1	20
β-strand	361	1	21
β-strand	364	1	22

Chain D: 15 helices, 26 β-strands

Element	Residues	Length	Sheet
β-strand	5-13	9	24
β-strand	16-25	10	24
β-strand	31-35	5	25
α-helix	38-40	3
α-helix	42-48	7
β-strand	59-62	4	24
β-strand	65-66	2	24
β-strand	80	1	26
α-helix	92-95	4
α-helix	113-116	4
α-helix	119-121	3
α-helix	133-135	3
α-helix	145-148	4
β-strand	154-155	2	25
β-strand	157	1	26
α-helix	169-182	14
β-strand	186-190	5	25
α-helix	194-200	7
β-strand	203-208	6	25
β-strand	211-216	6	25
α-helix	218-223	6
β-strand	227	1	27
α-helix	228-233	6
α-helix	238-239	2
β-strand	240-250	11	28
β-strand	253-257	5	28
β-strand	265-268	4	28
β-strand	270	1	29
β-strand	280-285	6	28
α-helix	287-289	3
β-strand	291	1	30
β-strand	299-309	11	30
β-strand	313-319	7	30
β-strand	327-332	6	30
β-strand	342-346	5	30
α-helix	349-351	3
β-strand	353-355	3	28
β-strand	360	1	27
β-strand	361	1	28
β-strand	364	1	29
α-helix	367-369	3

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Maltose/maltodextrin transport ATP-binding protein malK	A, B, C, D	protein	381	Escherichia coli	P68187 (AlphaFold model)

Sequence of entity 1 (A, B, C, D), FASTA

>1Q1B_1 Maltose/maltodextrin transport ATP-binding protein malK (chains A, B, C, D)
MASVQLQNVTKAWGEVVVSKDINLDIHEGEFVVFVGPSGCGKSTLLRMIAGLETITSGDL
FIGEKRMNDTPPAERGVGMVFQSYALYPHLSVAENMSFGLKLAGAKKEVINQRVNQVAEV
LQLAHLLDRKPKALSGGQRQRVAIGRTLVAEPSVFLLDEPLSNLDAALRVQMRIEISRLH
KRLGRTMIYVTHDQVEAMTLADKIVVLDAGRVAQVGKPLELYHYPADRFVAGFIGSPKMN
FLPVKVTATAIDQVQVELPMPNRQQVWLPVESRDVQVGANMSLGIRPEHLLPSDIADVIL
EGEVQVVEQLGNETQIHIQIPSIRQNLVYRQNDVVLVEEGATFAIGLPPERCHLFREDGT
ACRRLHKEPGVESASHHHHHH

Primary citation

A tweezer-like motion of the ATP-binding cassette dimer in an ABC transport cycle. Chen, J., Lu, G., Lin, J. et al. Mol Cell (2003) 12:651-661. DOI 10.1016/j.molcel.2003.08.004 · PubMed

Other PDB entries of the same protein (UniProt P68187 (AlphaFold model), which also has an AlphaFold model), best resolution first:

3RLF 2.2 Å, Crystal structure of the maltose-binding protein/maltose transporter complex in an…
2AWN 2.3 Å, Crystal structure of the ADP-Mg-bound E. Coli MALK (Crystallized with ATP-Mg)
3PUW 2.3 Å, Crystal Structure of an outward-facing MBP-Maltose transporter complex bound to ADP-AlF4
3PUX 2.3 Å, Crystal Structure of an outward-facing MBP-Maltose transporter complex bound to ADP-BeF3
4KI0 2.38 Å, Crystal structure of the maltose-binding protein/maltose transporter complex in an…
3PUV 2.4 Å, Crystal Structure of an outward-facing MBP-Maltose transporter complex bound to ADP-VO4
1Q12 2.6 Å, Crystal Structure of the ATP-bound E. coli MalK
3GD7 2.7 Å, Crystal structure of human NBD2 complexed with N6-Phenylethyl-ATP (P-ATP)
2AWO 2.8 Å, Crystal structure of the ADP-Mg-bound E. Coli MALK (Crystallized with ADP-Mg)
1Q1E 2.9 Å, The ATPase component of E. coli maltose transporter (MalK) in the nucleotide-free form
3PUZ 2.9 Å, Crystal Structure of a pre-translocation state MBP-Maltose transporter complex bound to…
4KHZ 2.9 Å, Crystal structure of the maltose-binding protein/maltose transporter complex in an…

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