3QTL | pdb_00003qtl

Structural Basis for Dual-inhibition Mechanism of a Non-classical Kazal-type Serine Protease Inhibitor from Horseshoe Crab in Complex with Subtilisin

External Resource: Annotation

Domain Annotation: SCOP/SCOPe Classification
Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
Domain Annotation: CATH
Protein Family Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification

Domain Annotation: SCOP/SCOPe Classification SCOP-e Database Homepage

Chains	Domain Info	Class	Fold	Superfamily	Family	Domain	Species	Provenance Source (Version)
C	d3qtlc_	Alpha and beta proteins (a/b)	Subtilisin-like	Subtilisin-like	Subtilases	automated matches	(Bacillus licheniformis ) [TaxId: 1402 ],	SCOPe (2.08)
B	d3qtlb_	Alpha and beta proteins (a/b)	Subtilisin-like	Subtilisin-like	Subtilases	automated matches	(Bacillus licheniformis ) [TaxId: 1402 ],	SCOPe (2.08)
A	d3qtla_	Alpha and beta proteins (a/b)	Subtilisin-like	Subtilisin-like	Subtilases	automated matches	(Bacillus licheniformis ) [TaxId: 1402 ],	SCOPe (2.08)

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
D	SCOP2B Superfamily	Kazal-type serine protease inhibitors	8070137	3000605	SCOP2B (2022-06-29)
C	SCOP2B Superfamily	Subtilisin-like	8099834	3000226	SCOP2B (2022-06-29)
B	SCOP2 Family	Subtilases	8099833	4000409	SCOP2 (2022-06-29)
B	SCOP2 Superfamily	Subtilisin-like	8099834	3000226	SCOP2 (2022-06-29)
A	SCOP2B Superfamily	Subtilisin-like	8099834	3000226	SCOP2B (2022-06-29)

Domain Annotation: ECOD Classification ECOD Database Homepage

Chains	Family Name	Domain Identifier	Architecture	Possible Homology	Homology	Topology	Family	Provenance Source (Version)
D	Kazal_1_1	e3qtlD1	A: few secondary structure elements	X: Kazal-type serine protease inhibitors-like	H: Kazal-type serine protease inhibitors (From Topology)	T: Kazal-type serine protease inhibitors	F: Kazal_1_1	ECOD (1.6)
C	Peptidase_S8	e3qtlC1	A: a/b three-layered sandwiches	X: Subtilisin-like	H: Subtilisin-like (From Topology)	T: Subtilisin-like	F: Peptidase_S8	ECOD (1.6)
B	Peptidase_S8	e3qtlB1	A: a/b three-layered sandwiches	X: Subtilisin-like	H: Subtilisin-like (From Topology)	T: Subtilisin-like	F: Peptidase_S8	ECOD (1.6)
A	Peptidase_S8	e3qtlA1	A: a/b three-layered sandwiches	X: Subtilisin-like	H: Subtilisin-like (From Topology)	T: Subtilisin-like	F: Peptidase_S8	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
C	3.40.50.200	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Peptidase S8/S53 domain	CATH (4.3.0)
B	3.40.50.200	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Peptidase S8/S53 domain	CATH (4.3.0)
A	3.40.50.200	Alpha Beta	3-Layer(aba) Sandwich	Rossmann fold	Peptidase S8/S53 domain	CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
D	PF00050	Kazal-type serine protease inhibitor domain (Kazal_1)	Kazal-type serine protease inhibitor domain	Usually indicative of serine protease inhibitors. However, kazal-like domains are also seen in the extracellular part of agrins, which are not known to be protease inhibitors. Kazal domains often occur in tandem arrays. Small alpha+beta fold containi ...	Usually indicative of serine protease inhibitors. However, kazal-like domains are also seen in the extracellular part of agrins, which are not known to be protease inhibitors. Kazal domains often occur in tandem arrays. Small alpha+beta fold containing three disulphides. Alignment also includes a single domain from transporters in the OATP/PGT family Swiss:P46721.	Domain
D	PF07648	Kazal-type serine protease inhibitor domain (Kazal_2)	Kazal-type serine protease inhibitor domain	Usually indicative of serine protease inhibitors. However, kazal-like domains are also seen in the extracellular part of agrins, which are not known to be protease inhibitors. Kazal domains often occur in tandem arrays. Small alpha+beta fold containi ...	Usually indicative of serine protease inhibitors. However, kazal-like domains are also seen in the extracellular part of agrins, which are not known to be protease inhibitors. Kazal domains often occur in tandem arrays. Small alpha+beta fold containing three disulphides.	Domain
A, B, C	PF00082	Subtilase family (Peptidase_S8)	Subtilase family	Subtilases are a family of serine proteases. They appear to have independently and convergently evolved an Asp/Ser/His catalytic triad, like that found in the trypsin serine proteases (see Pfam:PF00089). Structure is an alpha/beta fold containing a 7 ...	Subtilases are a family of serine proteases. They appear to have independently and convergently evolved an Asp/Ser/His catalytic triad, like that found in the trypsin serine proteases (see Pfam:PF00089). Structure is an alpha/beta fold containing a 7-stranded parallel beta sheet, order 2314567.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
D	Kazal-type serine protease inhibitor SPI-1	-	-	-
A, B, C	Subtilisin-like serin protease	peptidase activity catalytic activity, acting on a protein serine hydrolase activity serine-type peptidase activity hydrolase activity serine-type endopeptidase activity catalytic activity endopeptidase activity	proteolysis metabolic process cellular process primary metabolic process protein metabolic process macromolecule metabolic process	cellular anatomical structure extracellular region extracellular space

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
D	IPR036058	Kazal domain superfamily	Homologous Superfamily
D	IPR002350	Kazal domain	Domain
A, B, C	IPR023828	Peptidase S8, subtilisin, Ser-active site	Active Site
A, B, C	IPR010259	Peptidase S8 propeptide/proteinase inhibitor I9	Domain
A, B, C	IPR022398	Peptidase S8, subtilisin, His-active site	Active Site
A, B, C	IPR000209	Peptidase S8/S53 domain	Domain
A, B, C	IPR015500	Peptidase S8, subtilisin-related	Family
A, B, C	IPR036852	Peptidase S8/S53 domain superfamily	Homologous Superfamily
A, B, C	IPR023827	Peptidase S8, subtilisin, Asp-active site	Active Site
A, B, C	IPR050131	Subtilisin-like serine protease	Family
A, B, C	IPR037045	Peptidase S8 propeptide/proteinase inhibitor I9 superfamily	Homologous Superfamily
A, B, C	IPR034202	Subtilisin Carlsberg-like catalytic domain	Domain

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.