SAXSdb — 3fil

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

Immunoglobulin G-binding protein G

;Streptococcus sp. 'group G' ;

UniProt P19909

State in the Current Structure

Assembly	Physical composition	Protein state	Molecular copy count	Associated components	Data consistency
1	Protein homooligomer	Homooligomer	Protein 2	CALCIUM ION × 1 water × 2	Consistent with protein count

Other States of the Same Protein in the Database

View Construct and Data Evidence

UniProt name	SPG2_STRSG
Isoform	—
PDB entities	1, 2
Chains and sequence ranges	Author chain A； PDBConstruct 2–56； UniProt 303–357 Author chain B； PDBConstruct 2–56； UniProt 303–357

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	3fil
Deposition date deposition_date	2008-12-12
Structure title title	Structural and energetic determinants for hyperstable variants of GB1 obtained from in-vitro evolution
Keywords keywords	;dimerization, beta sheet, alpha helix, improved hydrophobic packing of core residues, PROTEIN BINDING, Cell wall, IgG-binding protein, Peptidoglycan-anchor, Secreted ;; PROTEIN BINDING
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.

3fil__assembly_1__model_1

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

Download this curve (.dat)

3fil__assembly_1__model_1 | I(q)

100 plotted points; both axes use logarithmic scales.

3fil__assembly_1__model_1 | P(r) · Pending

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

Rg（Guinier）	15.39 Å
Rg (electron density)	14.08 Å
Total Rg	15.30 Å
Atom count	879
Residues	111
Excluded volume	15810 Å³
Maximum q	0.500 Å⁻¹

Assembly	Model	Structure unit	Oligomeric description	Status	CRYSOL	Actions
1	1	`3fil__assembly_1__model_1`	dimeric （2）	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 (4)

Entity 1 Entity 1 polymer

Description description	Immunoglobulin G-binding protein G
Molecular weight formula_weight	6250.0 kDa
Mutation mutation	T2Q, E15V, T16L, T18I, N37L
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	1185

MQYKLILNGKTLKGVLTIEAVDAATAEKVFKQYANDLGVDGEWTYDDATKTFTVTE

Source Source

Source organism organism	;Streptococcus sp. 'group G' ;
NCBI taxonomy ID ncbi_taxonomy_id	1320
Host organism host_organism	Escherichia coli

Entity 2 Entity 2 polymer

Description description	Immunoglobulin G-binding protein G
Molecular weight formula_weight	6222.0 kDa
Mutation mutation	T2Q, E15V, T16L, T18I, N37L
Source method src_method	man
Copy count entity_count	1

Polymer Polymer

Polymer type type	polypeptide(L)
Chain IDs strand_id	B

MQYKLILNGKTLKGVLTIEAVDAATAEKVFKQYANDLGVDGEWTYDDATKTFTVTE

Source Source

Source organism organism	;Streptococcus sp. 'group G' ;
NCBI taxonomy ID ncbi_taxonomy_id	1320
Host organism host_organism	Escherichia coli

Entity 3 Entity 3 non-polymer

Description description	CALCIUM ION
Molecular weight formula_weight	40.1 kDa
Source method src_method	syn
Copy count entity_count	1

Entity 4 Entity 4 water

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	239

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6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

Domain ID domain_id	d3fila_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.15 — beta-Grasp (ubiquitin-like)
Superfamily Superfamily superfamily	d.15.7 — Immunoglobulin-binding domains
Family Family family	d.15.7.1 — Immunoglobulin-binding domains

Domain ID domain_id	d3filb_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.15 — beta-Grasp (ubiquitin-like)
Superfamily Superfamily superfamily	d.15.7 — Immunoglobulin-binding domains
Family Family family	d.15.7.1 — Immunoglobulin-binding domains

CATH v4.4 (2 domains)

Domain ID domain_id	3filA00
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	20 — Ubiquitin-like (UB roll)
Homologous superfamily homologous superfamily	10 —

Domain ID domain_id	3filB00
Class class	3 — Alpha Beta
Architecture architecture	10 — Roll
Topology topology	20 — Ubiquitin-like (UB roll)
Homologous superfamily homologous superfamily	10 —

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Unit-cell length a length_a	29.694 Å
Unit-cell length b length_b	38.930 Å
Unit-cell length c length_c	83.326 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	4

Space group space_group	P 21 21 21
Space-group number int_tables_number	19
Crystal system crystal_system	—

Resolution resolution	0.880 Å
Low-resolution limit resolution_low	19.466 Å
R factor r_factor	0.1250
R_work r_work	0.1239
R_free r_free	0.1493

Structural and energetic determinants for hyperstable variants of GB1 obtained from in-vitro evolution

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

Immunoglobulin G-binding protein G

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

3fil__assembly_1__model_1

3fil__assembly_1__model_1 | I(q)

3fil__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)

Structural and energetic determinants for hyperstable variants of GB1 obtained from in-vitro evolution

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

Immunoglobulin G-binding protein G

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

3fil__assembly_1__model_1

3fil__assembly_1__model_1 | I(q)

3fil__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 (4)

Entity 1 Entity 1 polymer

Polymer Polymer

Source Source

Entity 2 Entity 2 polymer

Polymer Polymer

Source Source

Entity 3 Entity 3 non-polymer

Entity 4 Entity 4 water

6. Fold Classification (SCOP + CATH) 4 domains

SCOP 2.08 (2 domains)

CATH v4.4 (2 domains)

7. Citations (1)