2WZA

Two intramolecular isopeptide bonds are identified in the crystal structure of the Streptococcus gordonii SspB C-terminal domain

External Resource: Annotation

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: SCOP2 Classification SCOP2 Database Homepage

Chains	Type	Family Name	Domain Identifier	Family Identifier	Provenance Source (Version)
A	SCOP2B Superfamily	Bacterial adhesin-like	8053852	3000723	SCOP2B (2022-06-29)
A	SCOP2B Superfamily	Bacterial adhesin-like	8053851	3000723	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)
A	isopep_sspB_C2	e2wzaA6	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Common fold of diphtheria toxin/transcription factors/cytochrome f	F: isopep_sspB_C2	ECOD (1.6)
A	Antigen_C	e2wzaA5	A: beta sandwiches	X: Immunoglobulin-like beta-sandwich	H: Immunoglobulin-related	T: Common fold of diphtheria toxin/transcription factors/cytochrome f	F: Antigen_C	ECOD (1.6)

Domain Annotation: CATH CATH Database Homepage

Chain	Domain	Class	Architecture	Topology	Homology	Provenance Source (Version)
A	2.60.40.740	Mainly Beta	Sandwich	Immunoglobulin-like		CATH (4.3.0)

Protein Family Annotation Pfam Database Homepage

Chains	Accession	Name	Description	Comments	Source
A	PF16364	Cell surface antigen C-terminus (Antigen_C)	Cell surface antigen C-terminus	This repeated domain is found at the C-terminus of cell surface antigens [1-3]. In the Streptococcus mutans antigen I/II there are three repeats of this domain, a cleft between the first two of these forms a binding site for the human salivary agglut ...	This repeated domain is found at the C-terminus of cell surface antigens [1-3]. In the Streptococcus mutans antigen I/II there are three repeats of this domain, a cleft between the first two of these forms a binding site for the human salivary agglutinin (SAG) [3].	Domain
A	PF17998	Cell surface antigen I/II C2 terminal domain (AgI_II_C2)	Cell surface antigen I/II C2 terminal domain	This is the second domain (C2) located in the C-terminal region found in antigen I/II type adhesin protein AspA from S. pyogenes. Together with C3, these two domains form an elongated structure, each domain adopts the DEv-IgG fold. Similar to the cla ...	This is the second domain (C2) located in the C-terminal region found in antigen I/II type adhesin protein AspA from S. pyogenes. Together with C3, these two domains form an elongated structure, each domain adopts the DEv-IgG fold. Similar to the classical IgG folds, it is comprised of two major antiparallel beta-sheets, designated ABED and CFG. For the C2-domain, there are two additional strands on the CFG sheet. Furthermore, sheets ABED and CFG are interconnected by several cross-connecting loops and one alpha-helix (DH1). The side chains of D982 and N996 in the C2-domain are involved in hydrogen bonding with the side chains of R1264 and N1295 in the C3 domain. Main chain hydrogen bonding can also be observed between S992 in C2 and N1189/G1191 in C3, furthermore stabilizing the interaction between the domains. The C2 domain contains one bound metal ion, modelled as Ca2+, and both the C2- and C3-domains are stabilized by conserved isopeptide bonds, which connect the beta-sheets of the central DEv-IgG motifs [1].Other members of this family include Major cell-surface adhesin PAc from Streptococcus mutans and SspB from Streptococcus gordonii.	Domain

Gene Ontology: Gene Product Annotation Gene Ontology Database Homepage

Chains	Polymer	Molecular Function	Biological Process	Cellular Component
A	AGGLUTININ RECEPTOR	cation binding ion binding binding metal ion binding small molecule binding	-	cellular anatomical structure extracellular region

InterPro: Protein Family Classification InterPro Database Homepage

Chains	Accession	Name	Type
A	IPR009578	Cell surface antigen I/II A repeat	Repeat
A	IPR013574	Glucan-binding protein C/Surface antigen I/II, V-domain	Domain
A	IPR041324	Antigen I/II, N-terminal	Domain
A	IPR032300	Cell surface antigen, C-terminal	Domain
A	IPR036234	Glucan-binding protein C/Surface antigen I/II, V-domain superfamily	Homologous Superfamily
A	IPR026345	Adhesin isopeptide-forming adherence domain	Domain
A	IPR021197	Cross-wall-targeting lipoprotein motif	Conserved Site
A	IPR019931	LPXTG cell wall anchor 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.