Annotations: 9X1H

Cryo-EM Structure of human complement C1s CUB domain in complex with RAY121

External Resource: Annotation

Domain Annotation: SCOP2 Classification
Domain Annotation: ECOD Classification
SAbDab Antibody Annotation
Gene Ontology: Gene Product Annotation
InterPro: Protein Family Classification
Pharos: Disease Associations

Domain Annotation: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
D [auth B]	SCOP2B Superfamily	EGF/Laminin-like	8033759	3000412	SCOP2B (2022-06-29)
D [auth B]	SCOP2B Superfamily	Spermadhesin, CUB domain	8033760	3001412	SCOP2B (2022-06-29)
F [auth A]	SCOP2B Superfamily	Spermadhesin, CUB domain	8033760	3001412	SCOP2B (2022-06-29)
F [auth A]	SCOP2B Superfamily	EGF/Laminin-like	8033759	3000412	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 [auth B]	DM10_dom	e9x1hB1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: DM10_dom	ECOD (v295.2)
F [auth A]	Sec23_trunk	e9x1hA1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: Sec23_trunk	ECOD (v295.2)
E [auth H]	Sec23_trunk	e9x1hH1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: Sec23_trunk	ECOD (v295.2)
C [auth I]	DM10_dom	e9x1hI1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: DM10_dom	ECOD (v295.2)
B [auth M]	IBN_N,Xpo1,CRM1_C,CRM1_repeat,CRM1_repeat_2,CRM1_repeat_3	e9x1hM1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: IBN_N,Xpo1,CRM1_C,CRM1_repeat,CRM1_repeat_2,CRM1_repeat_3	ECOD (v295.2)
A [auth L]	IBN_N,Xpo1,CRM1_C,CRM1_repeat,CRM1_repeat_2,CRM1_repeat_3	e9x1hL1	A: alpha arrays	X: Hypothetical protein YqbG-like	H: Hypothetical protein YqbG-like	T: alpha/beta-Hydrolases	F: IBN_N,Xpo1,CRM1_C,CRM1_repeat,CRM1_repeat_2,CRM1_repeat_3	ECOD (v295.2)

SAbDab Antibody Annotation SAbDab Database Homepage

Chain	Chain Class	Chain Subclass	Chain Type	Antigen Name(s)	Provenance Source
C [auth I], E [auth H]	Heavy Chain	IGHV4	-	complement c1s subcomponent heavy chain	SAbDab (2026-10-23)
A [auth L], B [auth M]	Light Chain	IGKV1	Kappa	complement c1s subcomponent heavy chain	SAbDab (2026-10-23)

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
D [auth B], F [auth A]	Complement C1s subcomponent heavy chain	cation binding ion binding binding calcium ion binding metal ion binding small molecule binding 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 cation binding ion binding binding calcium ion binding metal ion binding small molecule binding 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 identical protein binding protein binding	adaptive immune response based on somatic recombination of immune receptors built from immunoglobulin superfamily domains lymphocyte mediated immunity humoral immune response response to stimulus positive regulation of biological process positive regulation of response to stimulus complement activation humoral immune response mediated by circulating immunoglobulin positive regulation of immune response leukocyte mediated immunity regulation of immune system process positive regulation of immune system process complement activation, classical pathway regulation of biological process adaptive immune response based on somatic recombination of immune receptors built from immunoglobulin superfamily domains lymphocyte mediated immunity humoral immune response response to stimulus positive regulation of biological process positive regulation of response to stimulus complement activation humoral immune response mediated by circulating immunoglobulin positive regulation of immune response leukocyte mediated immunity regulation of immune system process positive regulation of immune system process complement activation, classical pathway regulation of biological process immune response biological regulation immunoglobulin mediated immune response adaptive immune response immune effector process regulation of response to stimulus immune system process B cell mediated immunity regulation of immune response activation of immune response proteolysis metabolic process cellular process primary metabolic process protein metabolic process macromolecule metabolic process	protein-containing complex cellular anatomical structure complement component C1 complex extracellular region extracellular protein-containing complex blood microparticle cell surface other organism part symbiont cell surface
C [auth I], E [auth H]	RAY121 Fab Heavy chain	-	-	-
A [auth L], B [auth M]	RAY121 Fab Light chain	-	-	-

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
D [auth B], F [auth A]	IPR009003	Peptidase S1, PA clan	Homologous Superfamily
D [auth B], F [auth A]	IPR018097	EGF-like calcium-binding, conserved site	Conserved Site
D [auth B], F [auth A]	IPR001314	Peptidase S1A, chymotrypsin family	Family
D [auth B], F [auth A]	IPR033116	Serine proteases, trypsin family, serine active site	Active Site
D [auth B], F [auth A]	IPR035914	Spermadhesin, CUB domain superfamily	Homologous Superfamily
D [auth B], F [auth A]	IPR001254	Serine proteases, trypsin domain	Domain
D [auth B], F [auth A]	IPR001881	EGF-like calcium-binding domain	Domain
D [auth B], F [auth A]	IPR000436	Sushi/SCR/CCP domain	Domain
D [auth B], F [auth A]	IPR000859	CUB domain	Domain
D [auth B], F [auth A]	IPR000152	EGF-type aspartate/asparagine hydroxylation site	PTM
D [auth B], F [auth A]	IPR024175	Peptidase S1A, complement C1r/C1S/mannan-binding	Family
D [auth B], F [auth A]	IPR035976	Sushi/SCR/CCP superfamily	Homologous Superfamily

Pharos: Disease Associations Pharos Homepage Annotation

Chains	Drug Target	Associated Disease
D [auth B], F [auth A]	: P09871	complement component C1s deficiency Ehlers-Danlos syndrome Hashimoto thyroiditis autoimmune hepatitis autoimmune disease Ehlers-Danlos syndrome, periodontal type 2 Hereditary Angioedema Types I and II esophageal adenocarcinoma subependymal giant cell astrocytoma hereditary angioedema type 2 invasive ductal breast carcinoma limb-girdle muscular dystrophy adrenal cortex carcinoma malignant colon neoplasm malignant mesothelioma complement component C1s deficiency Ehlers-Danlos syndrome Hashimoto thyroiditis autoimmune hepatitis autoimmune disease Ehlers-Danlos syndrome, periodontal type 2 Hereditary Angioedema Types I and II esophageal adenocarcinoma subependymal giant cell astrocytoma hereditary angioedema type 2 invasive ductal breast carcinoma limb-girdle muscular dystrophy adrenal cortex carcinoma malignant colon neoplasm malignant mesothelioma chronic kidney disease myopathy pancreatic ductal adenocarcinoma diabetes mellitus pancreatic intraductal papillary-mucinous neoplasm with low grade dysplasia Ehlers-Danlos syndrome, periodontal type 1 psoriasis gastric carcinoma ulcerative colitis head and neck cancer juvenile dermatomyositis lung cancer angioedema malignant ependymoma malignant pancreatic neoplasm chronic obstructive pulmonary disease non-small cell lung carcinoma cystic fibrosis pancreatic intraductal papillary-mucinous carcinoma Duchenne muscular dystrophy pilocytic astrocytoma Sjogren syndrome Emery-Dreifuss muscular dystrophy glioblastoma heart disease large cell medulloblastoma lung carcinoma atopic eczema malignant glioma Becker muscular dystrophy medulloblastoma ovarian cancer dermatomyositis pancreatic intraductal papillary-mucinous neoplasm pituitary cancer