8gs8

cryo-EM structure of the human respiratory complex II

Method: ELECTRON MICROSCOPY

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

Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial

Homo sapiens

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial × 1 （P21912） Succinate dehydrogenase cytochrome b560 subunit, mitochondrial × 1 （Q99643） Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial × 1 （O14521） FLAVIN-ADENINE DINUCLEOTIDE × 1 FE2/S2 (INORGANIC) CLUSTER × 1 IRON/SULFUR CLUSTER × 1 FE3-S4 CLUSTER × 1 UBIQUINONE-1 × 1 PROTOPORPHYRIN IX CONTAINING FE × 1 (1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SDHA_HUMAN
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–664； UniProt 1–664

Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial

Homo sapiens

UniProt P21912

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial × 1 （P31040） Succinate dehydrogenase cytochrome b560 subunit, mitochondrial × 1 （Q99643） Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial × 1 （O14521） FLAVIN-ADENINE DINUCLEOTIDE × 1 FE2/S2 (INORGANIC) CLUSTER × 1 IRON/SULFUR CLUSTER × 1 FE3-S4 CLUSTER × 1 UBIQUINONE-1 × 1 PROTOPORPHYRIN IX CONTAINING FE × 1 (1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SDHB_HUMAN
Isoform	—
PDB entities	2
Chains and sequence ranges	Author chain B； PDBConstruct 1–280； UniProt 1–280

Succinate dehydrogenase cytochrome b560 subunit, mitochondrial

Homo sapiens

UniProt Q99643

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial × 1 （P31040） Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial × 1 （P21912） Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial × 1 （O14521） FLAVIN-ADENINE DINUCLEOTIDE × 1 FE2/S2 (INORGANIC) CLUSTER × 1 IRON/SULFUR CLUSTER × 1 FE3-S4 CLUSTER × 1 UBIQUINONE-1 × 1 PROTOPORPHYRIN IX CONTAINING FE × 1 (1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	C560_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain C； PDBConstruct 1–169； UniProt 1–169

Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial

Homo sapiens

UniProt O14521

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein heterocomplex	Heteromer	Protein 4	Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial × 1 （P31040） Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial × 1 （P21912） Succinate dehydrogenase cytochrome b560 subunit, mitochondrial × 1 （Q99643） FLAVIN-ADENINE DINUCLEOTIDE × 1 FE2/S2 (INORGANIC) CLUSTER × 1 IRON/SULFUR CLUSTER × 1 FE3-S4 CLUSTER × 1 UBIQUINONE-1 × 1 PROTOPORPHYRIN IX CONTAINING FE × 1 (1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	DHSD_HUMAN
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain D； PDBConstruct 1–159； UniProt 1–159

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	8gs8
Deposition date deposition_date	2022-09-05
Structure title title	cryo-EM structure of the human respiratory complex II
Keywords keywords	succinate dehydrogenase, electron transport chain, human mitochondria, OXIDOREDUCTASE, oxidative phosphorylation; OXIDOREDUCTASE
Experimental Method method	ELECTRON MICROSCOPY

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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.

8gs8__assembly_1__model_1

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

Download this curve (.dat)

8gs8__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

8gs8__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	32.63 Å
Rg (electron density)	33.21 Å
Total Rg	33.45 Å
Atom count	8637
Residues	1090
Excluded volume	154220 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`8gs8__assembly_1__model_1`	tetrameric （4）	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 (11)

Entity 1 Entity 1 polymer

Description description	Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial
Molecular weight formula_weight	72786.5 kDa
EC 编号 ec_number	1.3.5.1
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	8637

MSGVRGLSRLLSARRLALAKAWPTVLQTGTRGFHFTVDGNKRASAKVSDSISAQYPVVDHEFDAVVVGAGGAGLRAAFGLSEAGFNTACVTKLFPTRSHTVAAQGGINAALGNMEEDNWRWHFYDTVKGSDWLGDQDAIHYMTEQAPAAVVELENYGMPFSRTEDGKIYQRAFGGQSLKFGKGGQAHRCCCVADRTGHSLLHTLYGRSLRYDTSYFVEYFALDLLMENGECRGVIALCIEDGSIHRIRAKNTVVATGGYGRTYFSCTSAHTSTGDGTAMITRAGLPCQDLEFVQFHPTGIYGAGCLITEGCRGEGGILINSQGERFMERYAPVAKDLASRDVVSRSMTLEIREGRGCGPEKDHVYLQLHHLPPEQLATRLPGISETAMIFAGVDVTKEPIPVLPTVHYNMGGIPTNYKGQVLRHVNGQDQIVPGLYACGEAACASVHGANRLGANSLLDLVVFGRACALSIEESCRPGDKVPPIKPNAGEESVMNLDKLRFADGSIRTSELRLSMQKSMQNHAAVFRVGSVLQEGCGKISKLYGDLKHLKTFDRGMVWNTDLVETLELQNLMLCALQTIYGAEARKESRGAHAREDYKVRIDEYDYSKPIQGQQKKPFEEHWRKHTLSYVDVGTGKVTLEYRPVIDKTLNEADCATVPPAIRSY

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 2 Entity 2 polymer

Description description	Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial
Molecular weight formula_weight	31674.8 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

MAAVVALSLRRRLPATTLGGACLQASRGAQTAAATAPRIKKFAIYRWDPDKAGDKPHMQTYEVDLNKCGPMVLDALIKIKNEVDSTLTFRRSCREGICGSCAMNINGGNTLACTRRIDTNLNKVSKIYPLPHMYVIKDLVPDLSNFYAQYKSIEPYLKKKDESQEGKQQYLQSIEEREKLDGLYECILCACCSTSCPSYWWNGDKYLGPAVLMQAYRWMIDSRDDFTEERLAKLQDPFSLYRCHTIMNCTRTCPKGLNPGKAIAEIKKMMATYKEKKASV

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 3 Entity 3 polymer

Description description	Succinate dehydrogenase cytochrome b560 subunit, mitochondrial
Molecular weight formula_weight	18632.2 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C

MAALLLRHVGRHCLRAHFSPQLCIRNAVPLGTTAKEEMERFWNKNIGSNRPLSPHITIYSWSLPMAMSICHRGTGIALSAGVSLFGMSALLLPGNFESYLELVKSLCLGPALIHTAKFALVFPLMYHTWNGIRHLMWDLGKGLKIPQLYQSGVVVLVLTVLSSMGLAAM

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 4 Entity 4 polymer

Description description	Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial
Molecular weight formula_weight	17064.0 kDa
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	D

MAVLWRLSAVCGALGGRALLLRTPVVRPAHISAFLQDRPIPEWCGVQHIHLSPSHHSGSKAASLHWTSERVVSVLLLGLLPAAYLNPCSAMDYSLAAALTLHGHWGLGQVVTDYVHGDALQKAAKAGLLALSALTFAGLCYFNYHDVGICKAVAMLWKL

Source Source

Source organism organism	Homo sapiens
Common name common_name	human
NCBI taxonomy ID ncbi_taxonomy_id	9606
Host organism host_organism	Homo sapiens

Entity 5 Entity 5 non-polymer

Description description	FLAVIN-ADENINE DINUCLEOTIDE
Molecular weight formula_weight	785.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 6 Entity 6 non-polymer

Description description	FE2/S2 (INORGANIC) CLUSTER
Molecular weight formula_weight	175.8 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 7 Entity 7 non-polymer

Description description	IRON/SULFUR CLUSTER
Molecular weight formula_weight	351.6 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 8 Entity 8 non-polymer

Description description	FE3-S4 CLUSTER
Molecular weight formula_weight	295.8 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 9 Entity 9 non-polymer

Description description	UBIQUINONE-1
Molecular weight formula_weight	250.3 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 10 Entity 10 non-polymer

Description description	PROTOPORPHYRIN IX CONTAINING FE
Molecular weight formula_weight	616.5 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 11 Entity 11 non-polymer

Description description	(1S)-2-{[(2-AMINOETHOXY)(HYDROXY)PHOSPHORYL]OXY}-1-[(PALMITOYLOXY)METHYL]ETHYL STEARATE
Molecular weight formula_weight	720.0 kDa
Source method src_method	syn
Copy count entity_count	1

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Unit-cell length a length_a	1.000 Å
Unit-cell length b length_b	1.000 Å
Unit-cell length c length_c	1.000 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	90.00 °
Molecules per unit cell Z z_pdb	—

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

Resolution resolution	2.86 Å
Resolution测定Method resolution_method	—
颗粒数 num_particles	114967

cryo-EM structure of the human respiratory complex II

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

Succinate dehydrogenase [ubiquinone] flavoprotein subunit, mitochondrial

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Succinate dehydrogenase [ubiquinone] iron-sulfur subunit, mitochondrial

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Succinate dehydrogenase cytochrome b560 subunit, mitochondrial

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

Succinate dehydrogenase [ubiquinone] cytochrome b small subunit, mitochondrial

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

8gs8__assembly_1__model_1

8gs8__assembly_1__model_1 | I(q)

8gs8__assembly_1__model_1 | P(r) · Pending

4. Crystallography and Experiment 4. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

冷冻电镜 EM 3D

5. Entities and Polymers Entities & Polymers (11)

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 non-polymer

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 non-polymer

Entity 11 Entity 11 non-polymer

7. Citations (1)