2QI9: ABC-transporter BtuCD

ABC-transporter BtuCD in complex with its periplasmic binding protein BtuF. Determined by X-ray diffraction at 2.6 Å resolution. Released 14 Aug 2007.

Method: X-ray diffraction
Resolution: 2.6 Å
Organism: Escherichia coli
Chains: 5
Atoms: 10,692
Mol. weight: 154.6 kDa
Ligands: PO4
Released: 14 Aug 2007

Explore 2QI9 in 3D Show helices and sheets RCSB PDB PDBe

Secondary structure: helices and β-sheets

2QI9 contains 74 α-helices and 43 β-strands across 5 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: 19 helices, 0 β-strands

Element	Residues	Length
α-helix	3-31	29
α-helix	40-42	3
α-helix	48-51	4
α-helix	52-56	5
α-helix	57-80	24
α-helix	88-91	4
α-helix	93-108	16
α-helix	114-136	23
α-helix	142-165	24
α-helix	171-179	9
α-helix	188-190	3
α-helix	191-194	4
α-helix	198-204	7
α-helix	208-215	8
α-helix	218-224	7
α-helix	228-250	23
α-helix	259-265	7
α-helix	272-295	24
α-helix	305-321	17

Chain B: 16 helices, 0 β-strands

Element	Residues	Length
α-helix	3-31	29
α-helix	48	1
α-helix	49-56	8
α-helix	57-80	24
α-helix	93-107	15
α-helix	115-137	23
α-helix	142-164	23
α-helix	169-179	11
α-helix	188-190	3
α-helix	191-204	14
α-helix	208-214	7
α-helix	218-224	7
α-helix	228-250	23
α-helix	256-265	10
α-helix	272-295	24
α-helix	305-320	16

Chain C: 13 helices, 15 β-strands

Element	Residues	Length	Sheet
β-strand	3-12	10	1
β-strand	14	1	1
β-strand	16-24	9	1
β-strand	28-32	5	2
α-helix	39-46	8
β-strand	53-58	6	1
β-strand	61-62	2	1
α-helix	63-65	3
α-helix	68-74	7
β-strand	75-78	4	2
α-helix	83-85	3
β-strand	89	1	3
α-helix	90-95	6
α-helix	104-113	10
α-helix	117-119	3
β-strand	123	1	3
α-helix	124-126	3
α-helix	129-144	16
β-strand	154-157	4	2
α-helix	166-181	16
β-strand	185-189	5	2
α-helix	193-199	7
β-strand	202-207	6	2
β-strand	210-216	7	2
α-helix	217-220	4
α-helix	223-230	8
β-strand	234-239	6	4
β-strand	242-247	6	4

Chain D: 13 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	3-12	10	5
β-strand	16-24	9	5
β-strand	28-32	5	6
α-helix	39-46	8
β-strand	53-58	6	5
β-strand	61-62	2	5
α-helix	63-65	3
α-helix	68-74	7
β-strand	75-78	4	6
α-helix	83-85	3
β-strand	89	1	7
α-helix	90-95	6
α-helix	104-113	10
α-helix	117-119	3
β-strand	123	1	7
α-helix	124-126	3
α-helix	129-142	14
β-strand	154-157	4	6
α-helix	166-181	16
β-strand	185-189	5	6
α-helix	193-199	7
β-strand	202-207	6	6
β-strand	210-216	7	6
α-helix	217-220	4
α-helix	223-230	8
β-strand	234-239	6	8
β-strand	242-247	6	8

Chain F: 13 helices, 14 β-strands

Element	Residues	Length	Sheet
β-strand	26-28	3	9
α-helix	31-39	9
β-strand	46	1	9
β-strand	47-48	2	10
α-helix	55-59	5
α-helix	61	1
β-strand	62-64	3	10
β-strand	69	1	10
α-helix	71-76	6
β-strand	81-84	4	9
α-helix	91-100	10
β-strand	103-106	4	9
α-helix	113-121	9
α-helix	123-125	3
α-helix	129-151	23
β-strand	156-160	5	11
β-strand	162	1	12
β-strand	168	1	12
α-helix	175-182	8
β-strand	185-187	3	11
β-strand	198	1	12
α-helix	205-207	3
β-strand	211-215	5	11
α-helix	222-227	6
β-strand	236-239	4	11
α-helix	241-245	5
α-helix	251-263	13

Molecules and chains

Molecule	Chains	Type	Length	Organism	UniProt
Vitamin B12 import system permease protein btuC	A, B	protein	326	Escherichia coli	P06609 (AlphaFold model)
Vitamin B12 import ATP-binding protein btuD	C, D	protein	249	Escherichia coli	P06611 (AlphaFold model)
Vitamin B12-binding protein btuF	F	protein	245	Escherichia coli	P37028 (AlphaFold model)

Sequence of entity 1 (A, B), FASTA

>2QI9_1 Vitamin B12 import system permease protein btuC (chains A, B)
MLTLARQQQRQNIRWLLSLSVLMLLALLLSLSAGEQWISPGDWFTPRGELFVWQIRLPRT
LAVLLVGAALAISGAVMQALFENPLAEPGLLGVSNGAGVGLIAAVLLGQGQLPNWALGLS
AIAGALIITLILLRFARRHLSTSRLLLAGVALGIISSALMTWAIYFSTSVDLRQLMYWMM
GGFGGVDWRQSWLMLALIPVLLWISSQSRPMNMLALGEISARQLGLPLWFWRNVLVAATG
WMVGVSVALAGAIGFIGLVIPHILRLSGLTDHRVLLPGCALAGASALLLADIVARLALAA
AELPIGVVTATLGAPVFIWLLLKAGR

Sequence of entity 2 (C, D), FASTA

>2QI9_2 Vitamin B12 import ATP-binding protein btuD (chains C, D)
MSIVMQLQDVAESTRLGPLSGEVRAGEILHLVGPNGAGKSTLLARMAGMTSGKGSIQFAG
QPLEAWSATKLALHRAYLSQQQTPPFATPVWHYLTLHQHDKTRTELLNDVAGALALDDKL
GRSTNQLSGGEWQRVRLAAVVLQITPQANPAGQLLLLDEPMNSLDVAQQSALDKILSALS
QQGLAIVMSSHDLNHTLRHAHRAWLLKGGKMLASGRREEVLTPPNLAQAYGMNFRRLDIE
GHRMLISTI

Sequence of entity 3 (F), FASTA

>2QI9_3 Vitamin B12-binding protein btuF (chains F)
AAPRVITLSPANTELAFAAGITPVGVSSYSDYPPQAQKIEQVSTWQGMNLERIVALKPDL
VIAWRGGNAERQVDQLASLGIKVMWVDATSIEQIANALRQLAPWSPQPDKAEQAAQSLLD
QYAQLKAQYADKPKKRVFLQFGINPPFTSGKESIQNQVLEVCGGENIFKDSRVPWPQVSR
EQVLARSPQAIVITGGPDQIPKIKQYWGEQLKIPVIPLTSDWFERASPRIILAAQQLCNA
LSQVD

Ligands and cofactors

ID	Name	Formula	Copies
PO4	Phosphate ion	O4 P	2

Water and common crystallization additives (1PE, PEG, SO4) are not listed.

Primary citation

Asymmetry in the structure of the ABC transporter-binding protein complex BtuCD-BtuF. Hvorup, R.N., Goetz, B.A., Niederer, M. et al. Science (2007) 317:1387-1390. DOI 10.1126/science.1145950 · PubMed

Other PDB entries of the same protein (UniProt P06609 (AlphaFold model), which also has an AlphaFold model), best resolution first:

4R9U 2.79 Å, Structure of vitamin B12 transporter BtuCD in a nucleotide-bound outward facing state
1L7V 3.2 Å, Bacterial ABC Transporter Involved in B12 Uptake
4FI3 3.47 Å, Structure of vitamin B12 transporter BtuCD-F in a nucleotide-bound state
4DBL 3.49 Å, Crystal structure of E159Q mutant of BtuCDF

Browse structure collections

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