2a74

Human Complement Component C3c

Method: X-RAY DIFFRACTION

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

Complement Component C3c

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Homooligomer	Protein 3 其他Polymer 1	2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose × 1 GLYCEROL × 7 NITRATE ION × 1 water × 3	Consistent with protein count
2	Other combination	Homooligomer	Protein 3 其他Polymer 1	2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose × 1 GLYCEROL × 6 NITRATE ION × 2 water × 3	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CO3_HUMAN
Isoform	—
PDB entities	1, 2, 3
Chains and sequence ranges	Author chain A； PDBConstruct 1–643； UniProt 23–665 Author chain D； PDBConstruct 1–643； UniProt 23–665 Author chain B； PDBConstruct 1–188； UniProt 749–936 Author chain E； PDBConstruct 1–188； UniProt 749–936 Author chain C； PDBConstruct 1–343； UniProt 1321–1663 Author chain F； PDBConstruct 1–343； UniProt 1321–1663

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	2a74
Deposition date deposition_date	2005-07-04
Structure title title	Human Complement Component C3c
Keywords keywords	Immune system; IMMUNE SYSTEM
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.

2a74__assembly_1__model_1

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

Download this curve (.dat)

2a74__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2a74__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	41.54 Å
Rg (electron density)	41.37 Å
Total Rg	41.46 Å
Atom count	8868
Residues	1109
Excluded volume	158690 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2a74__assembly_1__model_1`	trimeric （3）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`2a74__assembly_2__model_1`	trimeric （3）	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 (7)

Entity 1 Entity 1 polymer

Description description	Complement Component C3c
Molecular weight formula_weight	71267.2 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,D
Atom count atom_count	18389

SPMYSIITPNILRLESEETMVLEAHDAQGDVPVTVTVHDFPGKKLVLSSEKTVLTPATNHMGNVTFTIPANREFKSEKGRNKFVTVQATFGTQVVEKVVLVSLQSGYLFIQTDKTIYTPGSTVLYRIFTVNHKLLPVGRTVMVNIENPEGIPVKQDSLSSQNQLGVLPLSWDIPELVNMGQWKIRAYYENSPQQVFSTEFEVKEYVLPSFEVIVEPTEKFYYIYNEKGLEVTITARFLYGKKVEGTAFVIFGIQDGEQRISLPESLKRIPIEDGSGEVVLSRKVLLDGVQNLRAEDLVGKSLYVSATVILHSGSDMVQAERSGIPIVTSPYQIHFTKTPKYFKPGMPFDLMVFVTNPDGSPAYRVPVAVQGEDTVQSLTQGDGVAKLSINTHPSQKPLSITVRTKKQELSEAEQATRTMQALPYSTVGNSNNYLHLSVLRTELRPGETLNVNFLLRMDRAHEAKIRYYTYLIMNKGRLLKAGRQVREPGQDLVVLPLSITTDFIPSFRLVAYYTLIGASGQREVVADSVWVDVKDSCVGSLVVKSGQSEDRQPVPGQQMTLKIEGDHGARVVLVAVDKGVFVLNKKNKLTQSKIWDVVEKADIGCTPGSGKDYAGVFSDAGLTFTSSSGQQTAQRAELQCPQP

Entity 2 Entity 2 polymer

Description description	Complement Component C3c
Molecular weight formula_weight	21521.8 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B,E

SNLDEDIIAEENIVSRSEFPESWLWNVEDLKEPPKNGISTKLMNIFLKDSITTWEILAVSMSDKKGICVADPFEVTVMQDFFIDLRLPYSVVRNEQVEIRAVLYNYRQNQELKVRVELLHNPAFCSLATTKRRHQQTVTIPPKSSLSVPYVIVPLKTGLQEVEVKAAVYHHFISDGVRKSLKVVPEGI

Entity 3 Entity 3 polymer

Description description	Complement Component C3c
Molecular weight formula_weight	39537.4 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	C,F

SEETKENEGFTVTAEGKGQGTLSVVTMYHAKAKDQLTCNKFDLKVTIKPAPETEKRPQDAKNTMILEICTRYRGDQDATMSILDISMMTGFAPDTDDLKQLANGVDRYISKYELDKAFSDRNTLIIYLDKVSHSEDDCLAFKVHQYFNVELIQPGAVKVYAYYNLEESCTRFYHPEKEDGKLNKLCRDELCRCAEENCFIQKSDDKVTLEERLDKACEPGVDYVYKTRLVKVQLSNDFDEYIMAIEQTIKSGSDEVQVGQQRTFISPIKCREALKLEEKKHYLMWGLSSDFWGEKPNLSYIIGKDTWVEHWPEEDECQDEENQKQCQDLGAFTESMVVFGCPN

Entity 4 Entity 4 branched

Description description	2-acetamido-2-deoxy-alpha-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose
Molecular weight formula_weight	424.4 kDa
Source method src_method	man
Copy count entity_count	2

Entity 5 Entity 5 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 kDa
Source method src_method	syn
Copy count entity_count	13

Entity 6 Entity 6 non-polymer

Description description	NITRATE ION
Molecular weight formula_weight	62.0 kDa
Source method src_method	syn
Copy count entity_count	3

Entity 7 Entity 7 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	611

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6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

Domain ID domain_id	2a74A01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74A02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74A03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1940 —

Domain ID domain_id	2a74A04
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2a74A05
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74A06
Class class	6 — Special
Architecture architecture	20 — Other non-globular
Topology topology	50 — N-terminal domain of TfIIb
Homologous superfamily homologous superfamily	160 —

Domain ID domain_id	2a74B01
Class class	2 — Mainly Beta
Architecture architecture	20 — Single Sheet
Topology topology	130 — S-adenosyl-L-methionine-dependent methyltransferases
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	2a74B02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2a74C01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	690 — Alpha-macroglobulin, receptor-binding domain

Domain ID domain_id	2a74C02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	120 —

Domain ID domain_id	2a74D01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74D02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74D03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1940 —

Domain ID domain_id	2a74D04
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2a74D05
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1930 — Macroglobulin (MG2) domain

Domain ID domain_id	2a74D06
Class class	6 — Special
Architecture architecture	20 — Other non-globular
Topology topology	50 — N-terminal domain of TfIIb
Homologous superfamily homologous superfamily	160 —

Domain ID domain_id	2a74E01
Class class	2 — Mainly Beta
Architecture architecture	20 — Single Sheet
Topology topology	130 — S-adenosyl-L-methionine-dependent methyltransferases
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	2a74E02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2a74F01
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	690 — Alpha-macroglobulin, receptor-binding domain

Domain ID domain_id	2a74F02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	50 — OB fold (Dihydrolipoamide Acetyltransferase, E2P)
Homologous superfamily homologous superfamily	120 —

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Unit-cell length a length_a	126.866 Å
Unit-cell length b length_b	246.863 Å
Unit-cell length c length_c	87.383 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	8

Space group space_group	P 21 21 2
Space-group number int_tables_number	18
Crystal system crystal_system	—

Resolution resolution	2.400 Å
Low-resolution limit resolution_low	40.000 Å
R factor r_factor	0.2165
R_work r_work	0.2148
R_free r_free	0.2753

Human Complement Component C3c

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

Complement Component C3c

State in the Current Structure

Other States of the Same Protein in the Database

2. Structure Basics 2. Structure Basics

3. Official assembly/model SAXS Official SAXS Profiles

2a74__assembly_1__model_1

2a74__assembly_1__model_1 | I(q)

2a74__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 (7)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 branched

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

7. Citations (1)

Human Complement Component C3c

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

Complement Component C3c

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

2a74__assembly_1__model_1

2a74__assembly_1__model_1 | I(q)

2a74__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 (7)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 polymer

Polymer Polymer

Entity 3 Entity 3 polymer

Polymer Polymer

Entity 4 Entity 4 branched

Entity 5 Entity 5 non-polymer

Entity 6 Entity 6 non-polymer

Entity 7 Entity 7 water

6. Fold Classification (SCOP + CATH) 20 domains

CATH v4.4 (20 domains)

7. Citations (1)