2xwb

Crystal Structure of Complement C3b in complex with Factors B and D

Method: X-RAY DIFFRACTION

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

COMPLEMENT C3B BETA CHAIN

OrganismNot specified

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT FACTOR B × 1 （P00751） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	Consistent with protein count
2	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT FACTOR B × 1 （P00751） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
3	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT FACTOR B × 1 （P00751） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
4	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT FACTOR B × 1 （P00751） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	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
Chains and sequence ranges	Author chain A； PDBConstruct 1–642； UniProt 23–664 Author chain C； PDBConstruct 1–642； UniProt 23–664 Author chain B； PDBConstruct 1–912； UniProt 752–1663 Author chain D； PDBConstruct 1–912； UniProt 752–1663

COMPLEMENT FACTOR B

HOMO SAPIENS

UniProt P00751

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	Consistent with protein count
2	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
3	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
4	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR D × 1 （P00746） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CFAB_HUMAN
Isoform	—
PDB entities	3
Chains and sequence ranges	Author chain F； PDBConstruct 1–730； UniProt 35–764 Author chain H； PDBConstruct 1–730； UniProt 35–764

COMPLEMENT FACTOR D

HOMO SAPIENS

UniProt P00746

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR B × 1 （P00751） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	Consistent with protein count
2	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR B × 1 （P00751） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
3	Other combination	Heteromer	Protein 4 其他Polymer 2	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR B × 1 （P00751） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 3 GLYCEROL × 1 water × 1	Consistent with protein count
4	Other combination	Heteromer	Protein 4 其他Polymer 3	COMPLEMENT C3B BETA CHAIN × 1 （P01024） ;COMPLEMENT C3B ALPHA' CHAIN ; × 1 （P01024） COMPLEMENT FACTOR B × 1 （P00751） 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 2 beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose × 1 MAGNESIUM ION × 2 2-acetamido-2-deoxy-beta-D-glucopyranose × 2 GLYCEROL × 1 water × 1	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	CFAD_HUMAN
Isoform	—
PDB entities	4
Chains and sequence ranges	Author chain I； PDBConstruct 1–228； UniProt 26–253 Author chain J； PDBConstruct 1–228； UniProt 26–253

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	2xwb
Deposition date deposition_date	2010-11-01
Structure title title	Crystal Structure of Complement C3b in complex with Factors B and D
Keywords keywords	IMMUNE SYSTEM, PRO-CONVERTASE, HYDROLASE, SERINE PROTEASE, CONFORMATIONAL CHANGES, ALTERNATIVE PATHWAY; HYDROLASE
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.

2xwb__assembly_4__model_1

Assembly 4 · Model 1 · CRYSOL 4.1.3-1-20251215 (887e7ef)

Download this curve (.dat)

2xwb__assembly_4__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

2xwb__assembly_4__model_1 | P(r) · Pending

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

Rg（Guinier）	47.63 Å
Rg (electron density)	47.35 Å
Total Rg	47.55 Å
Atom count	19657
Residues	2483
Excluded volume	349770 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`2xwb__assembly_1__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
2	1	`2xwb__assembly_2__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
3	1	`2xwb__assembly_3__model_1`	tetrameric （4）	Success	4.1.3-1-20251215 (887e7ef)	View Download
4	1	`2xwb__assembly_4__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 (10)

Entity 1 Entity 1 polymer

Description description	COMPLEMENT C3B BETA CHAIN
Molecular weight formula_weight	71154.0 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	A,C
Atom count atom_count	39285

SPMYSIITPNILRLESEETMVLEAHDAQGDVPVTVTVHDFPGKKLVLSSEKTVLTPATNHMGNVTFTIPANREFKSEKGRNKFVTVQATFGTQVVEKVVLVSLQSGYLFIQTDKTIYTPGSTVLYRIFTVNHKLLPVGRTVMVNIENPEGIPVKQDSLSSQNQLGVLPLSWDIPELVNMGQWKIRAYYENSPQQVFSTEFEVKEYVLPSFEVIVEPTEKFYYIYNEKGLEVTITARFLYGKKVEGTAFVIFGIQDGEQRISLPESLKRIPIEDGSGEVVLSRKVLLDGVQNPRAEDLVGKSLYVSATVILHSGSDMVQAERSGIPIVTSPYQIHFTKTPKYFKPGMPFDLMVFVTNPDGSPAYRVPVAVQGEDTVQSLTQGDGVAKLSINTHPSQKPLSITVRTKKQELSEAEQATRTMQALPYSTVGNSNNYLHLSVLRTELRPGETLNVNFLLRMDRAHEAKIRYYTYLIMNKGRLLKAGRQVREPGQDLVVLPLSITTDFIPSFRLVAYYTLIGASGQREVVADSVWVDVKDSCVGSLVVKSGQSEDRQPVPGQQMTLKIEGDHGARVVLVAVDKGVFVLNKKNKLTQSKIWDVVEKADIGCTPGSGKDYAGVFSDAGLTFTSSSGQQTAQRAELQCPQ

Entity 2 Entity 2 polymer

Description description	;COMPLEMENT C3B ALPHA' CHAIN ;
Molecular weight formula_weight	103759.8 kDa
Source method src_method	nat
Copy count entity_count	2

Polymer Polymer

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

DEDIIAEENIVSRSEFPESWLWNVEDLKEPPKNGISTKLMNIFLKDSITTWEILAVSMSDKKGICVADPFEVTVMQDFFIDLRLPYSVVRNEQVEIRAVLYNYRQNQELKVRVELLHNPAFCSLATTKRRHQQTVTIPPKSSLSVPYVIVPLKTGLQEVEVKAAVYHHFISDGVRKSLKVVPEGIRMNKTVAVRTLDPERLGREGVQKEDIPPADLSDQVPDTESETRILLQGTPVAQMTEDAVDAERLKHLIVTPSGCGEENMIGMTPTVIAVHYLDETEQWEKFGLEKRQGALELIKKGYTQQLAFRQPSSAFAAFVKRAPSTWLTAYVVKVFSLAVNLIAIDSQVLCGAVKWLILEKQKPDGVFQEDAPVIHQEMIGGLRNNNEKDMALTAFVLISLQEAKDICEEQVNSLPGSITKAGDFLEANYMNLQRSYTVAIAGYALAQMGRLKGPLLNKFLTTAKDKNRWEDPGKQLYNVEATSYALLALLQLKDFDFVPPVVRWLNEQRYYGGGYGSTQATFMVFQALAQYQKDAPDHQELNLDVSLQLPSRSSKITHRIHWESASLLRSEETKENEGFTVTAEGKGQGTLSVVTMYHAKAKDQLTCNKFDLKVTIKPAPETEKRPQDAKNTMILEICTRYRGDQDATMSILDISMMTGFAPDTDDLKQLANGVDRYISKYELDKAFSDRNTLIIYLDKVSHSEDDCLAFKVHQYFNVELIQPGAVKVYAYYNLEESCTRFYHPEKEDGKLNKLCRDELCRCAEENCFIQKSDDKVTLEERLDKACEPGVDYVYKTRLVKVQLSNDFDEYIMAIEQTIKSGSDEVQVGQQRTFISPIKCREALKLEEKKHYLMWGLSSDFWGEKPNLSYIIGKDTWVEHWPEEDECQDEENQKQCQDLGAFTESMVVFGCPN

Entity 3 Entity 3 polymer

Description description	COMPLEMENT FACTOR B
Molecular weight formula_weight	82156.7 kDa
EC 编号 ec_number	3.4.21.47
Mutation mutation	YES
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

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

GSCSLEGVEIKGGSFRLLQEGQALEYVCPSGFYPYPVQTRTCRSTGSWSTLKTQDQKTVRKAECRAIHCPRPHDFENGEYWPRSPYYNVSDEISFHCYDGYTLRGSANRTCQVNGRWSGQTAICDNGAGYCSNPGIPIGTRKVGSQYRLEDSVTYHCSRGLTLRGSQRRTCQEGGSWSGTEPSCQDSFMYDTPQEVAEAFLSSLTETIEGVDAEDGHGPGEQQKRKIVLDPSGSMNIYLVLDGSGSIGASDFTGAKKCLVNLIEKVASYGVKPRYGLVTYATYPKIWVKVSEADSSNADWVTKQLNEINYEDHKLKSGTNTKKALQAVYSMMSWPDDVPPEGWNRTRHVIILMTDGLHNMGGDPITVIDEIRDLLYIGKDRKNPREDYLDVYVFGVGPLVNQVNINALASKKDNEQHVFKVKDMENLEDVFYQMIDESQSLSLCGMVWEHRKGTDYHKQPWQAKISVIRPSKGHESCMGAVVSEYFVLTAAHCFTVDDKEHSIKVSVGGEKRDLEIEVVLFHPNYNINGKKEAGIPEFYDYDVALIKLKNKLKYGQTIRPICLPCTEGTTRALRLPPTTTCQQQKEELLPAQDIKALFVSEEEKKLTRKEVYIKNGDKKGSCERDAQYAPGYDKVKDISEVVTPRFLCTGGVSPYADPNTCRGDSGGPLIVHKRSRFIQVGVISWGVVDVCKNQKRQKQVPAHARDFHINLFQVLPWLKEKLQDEDLGFLAA

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	COMPLEMENT FACTOR D
Molecular weight formula_weight	24422.8 kDa
EC 编号 ec_number	3.4.21.46
Mutation mutation	YES
Source method src_method	man
Copy count entity_count	2

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	I,J

ILGGREAEAHARPYMASVQLNGAHLCGGVLVAEQWVLSAAHCLEDAADGKVQVLLGAHSLSQPEPSKRLYDVLRAVPHPDSQPDTIDHDLLLLQLSEKATLGPAVRPLPWQRVDRDVAPGTLCDVAGWGIVNHAGRRPDSLQHVLLPVLDRATCNRRTHHDGAITERLMCAESNRRDSCKGDAGGPLVCGGVLEGVVTSGSRVCGNRKKPGIYTRVASYAAWIDSVLA

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 branched

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	424.4 kDa
Source method src_method	man
Copy count entity_count	3

Entity 6 Entity 6 branched

Description description	beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	586.5 kDa
Source method src_method	man
Copy count entity_count	2

Entity 7 Entity 7 non-polymer

Description description	MAGNESIUM ION
Molecular weight formula_weight	24.3 kDa
Source method src_method	syn
Copy count entity_count	4

Entity 8 Entity 8 non-polymer

Description description	2-acetamido-2-deoxy-beta-D-glucopyranose
Molecular weight formula_weight	221.2 kDa
Source method src_method	man
Copy count entity_count	5

Entity 9 Entity 9 non-polymer

Description description	GLYCEROL
Molecular weight formula_weight	92.1 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	4

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6. Fold Classification (SCOP + CATH) 32 domains

CATH v4.4 (32 domains)

Domain ID domain_id	2xwbA01
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	2xwbA02
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	2xwbA03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1940 —

Domain ID domain_id	2xwbA04
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2xwbA05
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	2xwbA06
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	2xwbB01
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	2xwbB02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2xwbB03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	120 — Jelly Rolls
Homologous superfamily homologous superfamily	1540 —

Domain ID domain_id	2xwbB04
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	2xwbB05
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	2xwbB06
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	2xwbC01
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	2xwbC02
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	2xwbC03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	1940 —

Domain ID domain_id	2xwbC04
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2xwbC05
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	2xwbC06
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	2xwbD01
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	2xwbD02
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	40 — Immunoglobulin-like
Homologous superfamily homologous superfamily	10 — Immunoglobulins

Domain ID domain_id	2xwbD03
Class class	2 — Mainly Beta
Architecture architecture	60 — Sandwich
Topology topology	120 — Jelly Rolls
Homologous superfamily homologous superfamily	1540 —

Domain ID domain_id	2xwbD04
Class class	1 — Mainly Alpha
Architecture architecture	50 — Alpha/alpha barrel
Topology topology	10 — Glycosyltransferase
Homologous superfamily homologous superfamily	20 —

Domain ID domain_id	2xwbD05
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	2xwbD06
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	2xwbF01
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	70 — Complement Module; domain 1
Homologous superfamily homologous superfamily	10 — Complement Module, domain 1

Domain ID domain_id	2xwbF03
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	410 — von Willebrand factor, type A domain

Domain ID domain_id	2xwbH01
Class class	2 — Mainly Beta
Architecture architecture	10 — Ribbon
Topology topology	70 — Complement Module; domain 1
Homologous superfamily homologous superfamily	10 — Complement Module, domain 1

Domain ID domain_id	2xwbH03
Class class	3 — Alpha Beta
Architecture architecture	40 — 3-Layer(aba) Sandwich
Topology topology	50 — Rossmann fold
Homologous superfamily homologous superfamily	410 — von Willebrand factor, type A domain

Domain ID domain_id	2xwbI01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	2xwbI02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	2xwbJ01
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

Domain ID domain_id	2xwbJ02
Class class	2 — Mainly Beta
Architecture architecture	40 — Beta Barrel
Topology topology	10 — Thrombin, subunit H
Homologous superfamily homologous superfamily	10 — Trypsin-like serine proteases

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Unit-cell length a length_a	108.275 Å
Unit-cell length b length_b	135.775 Å
Unit-cell length c length_c	149.975 Å
Unit-cell angle α angle_alpha	95.47 °
Unit-cell angle β angle_beta	110.69 °
Unit-cell angle γ angle_gamma	113.39 °
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	3.490 Å
Low-resolution limit resolution_low	65.950 Å
R factor r_factor	0.1920
R_work r_work	0.1890
R_free r_free	0.2440

Crystal Structure of Complement C3b in complex with Factors B and D

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

COMPLEMENT C3B BETA CHAIN

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

COMPLEMENT FACTOR B

State in the Current Structure

Other States of the Same Protein in the Database

Monomer

Homodimer

Homotetramer

Other homooligomers

Heteromeric or nucleic-acid complex

COMPLEMENT FACTOR D

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

2xwb__assembly_4__model_1

2xwb__assembly_4__model_1 | I(q)

2xwb__assembly_4__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

Entity 2 Entity 2 polymer

Polymer Polymer

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 branched

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) 32 domains

CATH v4.4 (32 domains)

7. Citations (1)