4ki0

Crystal structure of the maltose-binding protein/maltose transporter complex in an outward-facing conformation bound to maltohexaose

Method: X-RAY DIFFRACTION

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1. Protein Identity and Related Structures Protein Identity & Related Structures

ABC transporter related protein

Escherichia coli

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 5 其他Polymer 1	Maltose-binding periplasmic protein × 1 （P0AEX9） Maltose transport system permease protein MalF × 1 （P02916） Binding-protein-dependent transport systems inner membrane component × 1 （C9QV46） alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose × 1 MAGNESIUM ION × 2 PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER × 2 UNDECYL-MALTOSIDE × 11 (1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE × 2 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	C9QV42_ECOD1
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–371； UniProt 1–371 Author chain B； PDBConstruct 1–371； UniProt 1–371

Maltose-binding periplasmic protein

Escherichia coli

UniProt P0AEX9

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 5 其他Polymer 1	ABC transporter related protein × 2 （C9QV42） Maltose transport system permease protein MalF × 1 （P02916） Binding-protein-dependent transport systems inner membrane component × 1 （C9QV46） alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose × 1 MAGNESIUM ION × 2 PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER × 2 UNDECYL-MALTOSIDE × 11 (1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE × 2 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	MALE_ECOLI
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain E； PDBConstruct 1–370； UniProt 27–396

Maltose transport system permease protein MalF

Escherichia coli

UniProt P02916

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 5 其他Polymer 1	ABC transporter related protein × 2 （C9QV42） Maltose-binding periplasmic protein × 1 （P0AEX9） Binding-protein-dependent transport systems inner membrane component × 1 （C9QV46） alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose × 1 MAGNESIUM ION × 2 PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER × 2 UNDECYL-MALTOSIDE × 11 (1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE × 2 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	MALF_ECOLI
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain F； PDBConstruct 1–514； UniProt 1–514

Binding-protein-dependent transport systems inner membrane component

Escherichia coli

UniProt C9QV46

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 5 其他Polymer 1	ABC transporter related protein × 2 （C9QV42） Maltose-binding periplasmic protein × 1 （P0AEX9） Maltose transport system permease protein MalF × 1 （P02916） alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose × 1 MAGNESIUM ION × 2 PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER × 2 UNDECYL-MALTOSIDE × 11 (1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE × 2 water × 5	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	C9QV46_ECOD1
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain G； PDBConstruct 1–296； UniProt 1–296

The page prioritizes protein identity, the current assembly, associated components, oligomeric state and cross-PDB links. Chain mapping and sequence ranges are retained as data evidence. Internal IDs, import timestamps and assembly operation expressions are maintenance fields and are not shown here.

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2. Structure Basics 2. Structure Basics

Entry ID entry_id	4ki0
Deposition date deposition_date	2013-05-01
Structure title title	Crystal structure of the maltose-binding protein/maltose transporter complex in an outward-facing conformation bound to maltohexaose
Keywords keywords	ABC transporter, ATPase Maltodextrin transporter, ATP binding maltodextrin binding, inner membrane, TRANSPORT PROTEIN; TRANSPORT PROTEIN
Experimental Method method	X-RAY DIFFRACTION

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3. Official assembly/model SAXS Official SAXS Profiles

This page reads only the latest assembly calculations. Every curve maps to an explicit PDB entry, official biological assembly and coordinate model.

4ki0__assembly_1__model_1

Assembly 1 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

4ki0__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

4ki0__assembly_1__model_1 | P(r) · Pending

P(r) will be calculated and displayed separately for the same assembly/model.

Rg（Guinier）	48.60 Å
Rg (electron density)	48.16 Å
Total Rg	48.09 Å
Atom count	15088
Residues	1891
Excluded volume	273330 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`4ki0__assembly_1__model_1`	pentameric （5）	Success	4.1.3-1-20251215 (887e7ef)	View Download

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4. Crystallography and Experiment 4. Crystallography & Experiment

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5. Entities and Polymers Entities & Polymers (10)

Entity 1 Entity 1 polymer

Description description	ABC transporter related protein
Molecular weight formula_weight	42184.5 kDa
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,B
Atom count atom_count	15618

MASVQLQNVTKAWGEVVVSKDINLDIHEGEFVVFVGPSGCGKSTLLRMIAGLETITSGDLFIGEKRMNDTPPAERGVGMVFQSYALYPHLSVAENMSFGLKLAGAKKEVINQRVNQVAEVLQLAHLLDRKPKALSGGQRQRVAIGRTLVAEPSVFLLDEPLSNLDAALRVQMRIEISRLHKRLGRTMIYVTHDQVEAMTLADKIVVLDAGRVAQVGKPLELYHYPADRFVAGFIGSPKMNFLPVKVTATAIDQVQVELPMPNRQQVWLPVESRDVQVGANMSLGIRPEHLLPSDIADVILEGEVQVVEQLGNETQIHIQIPSIRQNLVYRQNDVVLVEEGATFAIGLPPERCHLFREDGTACRRLHKEPGVASASHHHHHH

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	536056
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Maltose-binding periplasmic protein
Molecular weight formula_weight	41898.3 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	E

KIEEGKLVIWINGDKGYNGLAEVGKKFEKDTGIKVTVEHPDKLEEKFPQVAATGDGPDIIFWAHDRFGGYAQSGLLAEITPDKAFQDKLYPFTWDAVRYNGKLIAYPIAVEALSLIYNKDLLPNPPKTWEEIPALDKELKAKGKSALMFNLQEPYFTWPLIAADGGYAFKYENGKYDIKDVGVDNAGAKAGLTFLVDLIKNKHMNADTDYSIAEAAFNKGETAMTINGPWAWSNIDTSKVNYGVTVLPTFKGQPSKPFVGVLSAGINAASPNKELAKEFLENYLLTDEGLEAVNKDKPLGAVALKSYEEELAKDPRIAATMENAQKGEIMPNIPQMSAFWYAVRTAVINAASGRQTVDEALKDAQTRITKASASHHHHHH

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	83333
Host organism host_organism	Escherichia coli

Entity 3 Entity 3 polymer

Description description	Maltose transport system permease protein MalF
Molecular weight formula_weight	57052.9 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	F

MDVIKKKHWWQSDALKWSVLGLLGLLVGYLVVLMYAQGEYLFAITTLILSSAGLYIFANRKAYAWRYVYPGMAGMGLFVLFPLVCTIAIAFTNYSSTNQLTFERAQEVLLDRSWQAGKTYNFGLYPAGDEWQLALSDGETGKNYLSDAFKFGGEQKLQLKETTAQPEGERANLRVITQNRQALSDITAILPDGNKVMMSSLRQFSGTQPLYTLDGDGTLTNNQSGVKYRPNNQIGFYQSITADGNWGDEKLSPGYTVTTGWKNFTRVFTDEGIQKPFLAIFVWTVVFSLITVFLTVAVGMVLACLVQWEALRGKAVYRVLLILPYAVPSFISILIFKGLFNQSFGEINMMLSALFGVKPAWFSDPTTARTMLIIVNTWLGYPYMMILCMGLLKAIPDDLYEASAMDGAGPFQNFFKITLPLLIKPLTPLMIASFAFNFNNFVLIQLLTNGGPDRLGTTTPAGYTDLLVNYTYRIAFEGGGGQDFGLAAAIATLIFLLVGALAIVNLKATRMKFD

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	83333
Host organism host_organism	Escherichia coli

Entity 4 Entity 4 polymer

Description description	Binding-protein-dependent transport systems inner membrane component
Molecular weight formula_weight	32246.2 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	G

MAMVQPKSQKARLFITHLLLLLFIAAIMFPLLMVVAISLRQGNFATGSLIPEQISWDHWKLALGFSVEQADGRITPPPFPVLLWLWNSVKVAGISAIGIVALSTTCAYAFARMRFPGKATLLKGMLIFQMFPAVLSLVALYALFDRLGEYIPFIGLNTHGGVIFAYLGGIALHVWTIKGYFETIDSSLEEAAALDGATPWQAFRLVLLPLSVPILAVVFILSFIAAITEVPVASLLLRDVNSYTLAVGMQQYLNPQNYLWGDFAAAAVMSALPITIVFLLAQRWLVNGLTAGGVKG

Source Source

Source organism organism	Escherichia coli
NCBI taxonomy ID ncbi_taxonomy_id	536056
Host organism host_organism	Escherichia coli

Entity 5 Entity 5 branched

Description description	alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose-(1-4)-alpha-D-glucopyranose
Molecular weight formula_weight	666.6 kDa
Source method src_method	man
Copy count entity_count	1

Entity 6 Entity 6 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 7 Entity 7 non-polymer

Description description	PHOSPHOAMINOPHOSPHONIC ACID-ADENYLATE ESTER
Molecular weight formula_weight	506.2 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 8 Entity 8 non-polymer

Description description	UNDECYL-MALTOSIDE
Molecular weight formula_weight	496.6 kDa
Source method src_method	syn
Copy count entity_count	11

Entity 9 Entity 9 non-polymer

Description description	(1R)-2-{[{[(2S)-2,3-DIHYDROXYPROPYL]OXY}(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL (11E)-OCTADEC-11-ENOATE
Molecular weight formula_weight	749.0 kDa
Source method src_method	syn
Copy count entity_count	2

Entity 10 Entity 10 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	508

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6. Fold Classification (SCOP + CATH) 23 domains

SCOP 2.08 (10 domains)

Domain ID domain_id	d4ki0a1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.37 — P-loop containing nucleoside triphosphate hydrolases
Superfamily Superfamily superfamily	c.37.1 — P-loop containing nucleoside triphosphate hydrolases
Family Family family	c.37.1.12 — ABC transporter ATPase domain-like

Domain ID domain_id	d4ki0a2
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.6 — MOP-like
Family Family family	b.40.6.3 — ABC-transporter additional domain

Domain ID domain_id	d4ki0a3
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d4ki0b1
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.37 — P-loop containing nucleoside triphosphate hydrolases
Superfamily Superfamily superfamily	c.37.1 — P-loop containing nucleoside triphosphate hydrolases
Family Family family	c.37.1.12 — ABC transporter ATPase domain-like

Domain ID domain_id	d4ki0b2
Class class	b — All beta proteins
Fold Fold fold	b.40 — OB-fold
Superfamily Superfamily superfamily	b.40.6 — MOP-like
Family Family family	b.40.6.3 — ABC-transporter additional domain

Domain ID domain_id	d4ki0b3
Class class	l — Artifacts
Fold Fold fold	l.1 — Tags
Superfamily Superfamily superfamily	l.1.1 — Tags
Family Family family	l.1.1.1 — Tags

Domain ID domain_id	d4ki0e_
Class class	c — Alpha and beta proteins (a/b)
Fold Fold fold	c.94 — Periplasmic binding protein-like II
Superfamily Superfamily superfamily	c.94.1 — Periplasmic binding protein-like II
Family Family family	c.94.1.1 — Phosphate binding protein-like

Domain ID domain_id	d4ki0f1
Class class	e — Multi-domain proteins (alpha and beta)
Fold Fold fold	e.70 — MalF N-terminal region-like
Superfamily Superfamily superfamily	e.70.1 — MalF N-terminal region-like
Family Family family	e.70.1.1 — MalF N-terminal region-like

Domain ID domain_id	d4ki0f2
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.58 — MetI-like
Superfamily Superfamily superfamily	f.58.1 — MetI-like
Family Family family	f.58.1.1 — MetI-like

Domain ID domain_id	d4ki0g_
Class class	f — Membrane and cell surface proteins and peptides
Fold Fold fold	f.58 — MetI-like
Superfamily Superfamily superfamily	f.58.1 — MetI-like
Family Family family	f.58.1.1 — MetI-like

CATH v4.4 (13 domains)

Domain ID domain_id	4ki0A01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	4ki0A02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	100 — RNA polymerase II/Efflux pump adaptor protein, barrel-sandwich hybrid domain

Domain ID domain_id	4ki0A03
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	140 — Nucleic acid-binding proteins

Domain ID domain_id	4ki0B01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	300 — P-loop containing nucleotide triphosphate hydrolases

Domain ID domain_id	4ki0B02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	100 — RNA polymerase II/Efflux pump adaptor protein, barrel-sandwich hybrid domain

Domain ID domain_id	4ki0B03
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	140 — Nucleic acid-binding proteins

Domain ID domain_id	4ki0E01
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	190 — D-Maltodextrin-Binding Protein; domain 2
Homologous superfamily homologous superfamily	10 — Periplasmic binding protein-like II

Domain ID domain_id	4ki0E02
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	190 — D-Maltodextrin-Binding Protein; domain 2
Homologous superfamily homologous superfamily	10 — Periplasmic binding protein-like II

Domain ID domain_id	4ki0F01
Class class	1 — Mainly Alpha
Architecture architecture	20 — Up-down Bundle
Topology topology	58 — Methane Monooxygenase Hydroxylase; Chain G, domain 1
Homologous superfamily homologous superfamily	370 — MalF N-terminal region-like

Domain ID domain_id	4ki0F02
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	650 — MalF N-terminal region-like
Homologous superfamily homologous superfamily	10 — MalF N-terminal region-like

Domain ID domain_id	4ki0F03
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	430 — Periplasmic binding protein-like II
Homologous superfamily homologous superfamily	10 — D-maltodextrin-binding protein, MBP

Domain ID domain_id	4ki0F04
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3720 — MetI-like fold
Homologous superfamily homologous superfamily	10 — MetI-like

Domain ID domain_id	4ki0G01
Class class	1 — Mainly Alpha
Architecture architecture	10 — Orthogonal Bundle
Topology topology	3720 — MetI-like fold
Homologous superfamily homologous superfamily	10 — MetI-like

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Unit-cell length a length_a	81.592 Å
Unit-cell length b length_b	96.631 Å
Unit-cell length c length_c	112.321 Å
Unit-cell angle α angle_alpha	85.30 °
Unit-cell angle β angle_beta	79.11 °
Unit-cell angle γ angle_gamma	73.00 °
Molecules per unit cell Z z_pdb	2

Space group space_group	P 1
Space-group number int_tables_number	1
Crystal system crystal_system	—

Resolution resolution	2.380 Å
Low-resolution limit resolution_low	19.820 Å
R factor r_factor	0.1939
R_work r_work	0.1921
R_free r_free	0.2283

Crystal structure of the maltose-binding protein/maltose transporter complex in an outward-facing conformation bound to maltohexaose

1. Protein Identity and Related Structures Protein Identity & Related Structures

ABC transporter related protein

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Maltose-binding periplasmic protein

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Maltose transport system permease protein MalF

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Binding-protein-dependent transport systems inner membrane component

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

4ki0__assembly_1__model_1

4ki0__assembly_1__model_1 | I(q)

4ki0__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

5. Entities and Polymers Entities & Polymers (10)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 polymer

Polymer Polymer

Source Source

Entity 4 Entity 4 polymer

Polymer Polymer

Source Source

Entity 5 Entity 5 branched

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 non-polymer

Entity 8 Entity 8 non-polymer

Entity 9 Entity 9 non-polymer

Entity 10 Entity 10 water

6. Fold Classification (SCOP + CATH) 23 domains

SCOP 2.08 (10 domains)

CATH v4.4 (13 domains)

7. Citations (1)