SAXSdb — 3ssi

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

STREPTOMYCES SUBTILISIN INHIBITOR

OrganismNot specified

State in the Current Structure

Assembly	Oligomeric State	Construct	Mutations and Modifications	Ligands, Ions and Associated Components	Method and Experimental Conditions	Structure Quality
1	Protein homooligomer Homooligomer Protein × 2 PDB declaration: dimeric（2） Consistent with protein copy count	Chain A； UniProt 32–144	Not recorded	No other associated polymer	X-RAY DIFFRACTION X-ray crystallization conditions：pH 7；pH 7.0	Resolution 2.30 Å

Other States of the Same Protein in the Database

Each row is a biological assembly of the same UniProt protein in another PDB entry. The “Difference from current entry” column identifies evidence-level differences; no tag means the currently parsed fields agree.

Other PDB	Difference from Current Entry 3SSI	Assembly / Oligomeric State	Construct	Mutations and Modifications	Ligands, Ions and Non-polymers	Method and Experimental Conditions	Structure Quality
2SIC REFINED CRYSTAL STRUCTURE OF THE COMPLEX OF SUBTILISIN BPN' AND STREPTOMYCES SUBTILISIN INHIBITOR AT 1.8 ANGSTROMS RESOLUTION Deposited 1991-04-01	Different construct Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric	Chain I 38–144（107 aa）	Not recorded	CA CALCIUM ION × 4	X-RAY DIFFRACTION mmCIF provides none of the parsed conditions	Resolution 1.80 Å
2TLD CRYSTAL STRUCTURE OF AN ENGINEERED SUBTILISIN INHIBITOR COMPLEXED WITH BOVINE TRYPSIN Deposited 1991-09-16	Different construct Different oligomeric state Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 2 PDB declaration: dimeric	Chain I 35–144（110 aa）	Not recorded	No recorded non-water small molecule	X-RAY DIFFRACTION mmCIF provides none of the parsed conditions	Resolution 2.60 Å
3SIC MOLECULAR RECOGNITION AT THE ACTIVE SITE OF SUBTILISIN BPN': CRYSTALLOGRAPHIC STUDIES USING GENETICALLY ENGINEERED PROTEINACEOUS INHIBITOR SSI (STREPTOMYCES SUBTILISIN INHIBITOR) Deposited 1991-08-30	Different construct Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric	Chain I 38–144（107 aa）	Not recorded	CA CALCIUM ION × 4	X-RAY DIFFRACTION mmCIF provides none of the parsed conditions	Resolution 1.80 Å
5SIC MOLECULAR RECOGNITION AT THE ACTIVE SITE OF SUBTILISIN BPN': CRYSTALLOGRAPHIC STUDIES USING GENETICALLY ENGINEERED PROTEINACEOUS INHIBITOR SSI (STREPTOMYCES SUBTILISIN INHIBITOR) Deposited 1991-11-18	Different construct Different oligomeric state Different ligand/ion Different experimental conditions Different structure-quality metrics	Assembly 1 Protein heterocomplex Heteromer；Protein × 4 PDB declaration: tetrameric	Chain I 38–144（107 aa）	Not recorded	CA CALCIUM ION × 4	X-RAY DIFFRACTION mmCIF provides none of the parsed conditions	Resolution 2.20 Å

4 other PDB entries and 4 assemblies. Open the comparison page and filter oligomeric states

View Construct and Data Evidence

UniProt name	SSI_STRAO
Isoform	—
PDB entities	1
Chains and sequence ranges	Author chain A； PDBConstruct 1–113； UniProt 32–144

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	3ssi
Deposition date deposition_date	1996-03-01
Structure title title	PROTEINASE INHIBITOR SSI (STREPTOMYCES SUBTILISIN, INHIBITOR) FROM STREPTOMYCES ALBOGRISEOLUS
Keywords keywords	SSI, SERINE PROTEASE INHIBITOR, SUBTILISIN BPN; SERINE PROTEASE INHIBITOR
Experimental Method method	X-RAY DIFFRACTION

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3. SAXS Parameters (CRYSOL theoretical calculation) 3. SAXS Parameters (CRYSOL)

Radius of gyration Rg (Guinier) rg_guinier	14.52 Å
Radius of gyration Rg (electron density) rg_electron	13.63 Å
Forward intensity I(0) i0	2630080.00
Molecular weight molecular_weight	11042.0 kDa
Excluded volume excluded_volume	13681 Å³
Envelope volume envelope_volume	15580 Å³
Hydration-shell volume shell_volume	10232 Å³
Envelope diameter envelope_diameter	52.4 Å
Shell Rg shell_rg	18.72 Å
Envelope Rg envelope_rg	14.07 Å
Shape Rg shape_rg	13.59 Å
Total Rg total_rg	14.81 Å
Total atoms total_atoms	772
Residues n_residues	108
Spherical-harmonic order n_harmonics	20
q range q_range	— – 0.5000 Å⁻¹
Data points n_points	101
Shell type shell_type	directional
Solvent electron density solvent_density	0.3340 e/Å³
Shell contrast contrast_shell	0.0300 e/Å³
CRYSOL version crysol_version	4.1.3

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4. P(r) Distance Distribution (GNOM inversion) 4. P(r) Analysis (GNOM)

Maximum dimension Dmax dmax	52.2 Å
Rg (real space) rg_real	14.49 Å
Rg uncertainty (real space) rg_real_error	0.45 Å
I(0) (real space) i0_real	2.6300e+06
I(0) uncertainty (real space) i0_real_error	3.2320e+04
Rg (reciprocal space) rg_reciprocal	14.49 Å
I(0) (reciprocal space) i0_reciprocal	2630000.0000
Solution quality estimate total_estimate	0.7697
Solution quality rating solution_quality	GOOD a GOOD solution
P(r) peaks n_peaks	3
Primary peak position r_peak_primary	17.8 Å
Skewness Skewness skewness	0.289
Kurtosis Kurtosis kurtosis	-0.127
Angular range angular_range	— – 0.5000 Å⁻¹
Current regularization parameter α current_alpha	0.0000
Highest regularization parameter α highest_alpha	356200.0000
Real-space data points n_real_points	80
GNOM version gnom_version	4.1.3
Quality Criteria quality_criteria	AN1: 0.000; Oscil: 0.684; Stabil: 1.000; Sysdev: 1.000; Positv: 1.000; Valcen: 0.951; Smooth: 0.000

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5. Crystallography and Experiment 5. Crystallography & Experiment

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6. Entities and Polymers Entities & Polymers (2)

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7. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

Domain ID domain_id	d3ssia_
Class class	d — Alpha and beta proteins (a+b)
Fold Fold fold	d.84 — Subtilisin inhibitor
Superfamily Superfamily superfamily	d.84.1 — Subtilisin inhibitor
Family Family family	d.84.1.1 — Subtilisin inhibitor

CATH v4.4 (1 domains)

Domain ID domain_id	3ssiA00
Class class	3 — Alpha Beta
Architecture architecture	30 — 2-Layer Sandwich
Topology topology	350 — Subtilisin Inhibitor
Homologous superfamily homologous superfamily	10 — Subtilisin inhibitor-like

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8. Citations (14)

Structural Modulation of the Protein Proteinase Inhibitor Ssi (Streptomyces Subtilisin Inhibitor)

To be Published

PRIMARY

Crystal Structure of an Engineered Subtilisin Inhibitor Complexed with Bovine Trypsin

Proc.Natl.Acad.Sci.USA (1992)

;Refined Crystal Structure of the Complex of Subtilisin Bpn' and Streptomyces Subtilisin Inhibitor at 1.8 A Resolution ;

J.Mol.Biol. (1991)

;Molecular Recognition at the Active Site of Subtilisin Bpn': Crystallographic Studies Using Genetically Engineered Proteinaceous Inhibitor Ssi (Streptomyces Subtilisin Inhibitor) ;

Protein Eng. (1991)

;Interactions of Streptomyces Subtilisin Inhibitor with Streptomyces Griseus Proteases a and B. Enzyme Kinetic and Computer Simulation Studies ;

J.Biochem.(Tokyo) (1985)

Untitled

Protein Protease Inhibitor: The Case of Streptomyces Subtilisin Inhibitor (Ssi) (1985)

;Crystal Structure at 2.6 A Resolution of the Complex of Subtilisin Bpn' with Streptomyces Subtilisin Inhibitor ;

J.Mol.Biol. (1984)

Solvent Accessibility and Microenvironment in a Bacterial Protein Proteinase Inhibitor Ssi (Streptomyces Subtilisin Inhibitor)

J.Biochem.(Tokyo) (1980)

Crystal Structures of Streptomyces Subtilisin Inhibitor and its Complex with Subtilisin Bpn

Nature (1979)

;Crystal Structure of the Complex of Subtilisin Bpn' with its Protein Inhibitor Streptomyces Subtilisin Inhibitor. The Structure at 4.3 Angstroms Resolution ;

J.Mol.Biol. (1979)

Crystal Structure of a Bacterial Protein Proteinase Inhibitor (Streptomyces Subtilisin Inhibitor) at 2.6 A Resolution

J.Mol.Biol. (1979)

Crystal Structure of a Protein Proteinase Inhibitor, Ssi (Streptomyces Subtilisin Inhibitor), at 4 A Resolution

J.Biochem.(Tokyo) (1978)

Crystal Structure of a Protein Proteinase Inhibitor, Streptomyces Subtilisin Inhibitor, at 2.3 Angstrom Resolution

J.Biochem.(Tokyo) (1977)

Crystallization and Preliminary X-Ray Investigation of a New Alkaline Protease Inhibitor and its Complex with Subtilisin Bpn

J.Mol.Biol. (1973)

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Unit-cell length a length_a	40.740 Å
Unit-cell length b length_b	40.740 Å
Unit-cell length c length_c	115.280 Å
Unit-cell angle α angle_alpha	90.00 °
Unit-cell angle β angle_beta	90.00 °
Unit-cell angle γ angle_gamma	120.00 °
Molecules per unit cell Z z_pdb	6

Space group space_group	P 31 2 1
Space-group number int_tables_number	152
Crystal system crystal_system	—

Resolution resolution	2.300 Å
Low-resolution limit resolution_low	6.000 Å
R factor r_factor	0.1850
R_work r_work	0.1850
R_free r_free	—

Description description	STREPTOMYCES SUBTILISIN INHIBITOR
Molecular weight formula_weight	11494.9 kDa
Source method src_method	nat
Copy count entity_count	1

Polymer type type	polypeptide(L)
Chain IDs strand_id	A
Atom count atom_count	803

PROTEINASE INHIBITOR SSI (STREPTOMYCES SUBTILISIN, INHIBITOR) FROM STREPTOMYCES ALBOGRISEOLUS

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

STREPTOMYCES SUBTILISIN INHIBITOR

State in the Current Structure

Other States of the Same Protein in the Database

SAXS scattering curve SAXS Profile

P(r) Distance Distribution P(r) Distribution

2. Structure Basics 2. Structure Basics

3. SAXS Parameters (CRYSOL theoretical calculation) 3. SAXS Parameters (CRYSOL)

4. P(r) Distance Distribution (GNOM inversion) 4. P(r) Analysis (GNOM)

5. Crystallography and Experiment 5. Crystallography & Experiment

Unit cell Unit Cell

Symmetry Symmetry

Refinement Refinement

Diffraction experiment Diffraction

6. Entities and Polymers Entities & Polymers (2)

Entity 1 Entity 1 polymer

Polymer Polymer

Entity 2 Entity 2 water

7. Fold Classification (SCOP + CATH) 2 domains

SCOP 2.08 (1 domains)

CATH v4.4 (1 domains)

8. Citations (14)

9. Files and Curves (10)

Files (7)

Curves (3)

Description description	water
Molecular weight formula_weight	18.0 kDa
Source method src_method	nat
Copy count entity_count	31

fit	/app/data/saxs_computation/ss/3ssi/3ssi.fit
pddf	/app/data/pr_computation/ss/3ssi/3ssi.pr.out
profile	/app/data/saxs_computation/ss/3ssi/3ssi.dat