Summary: C-terminus of bacterial fibrinogen-binding adhesin
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SdrG C terminal protein domain Edit Wikipedia article
|SdrG, C-terminal domain|
Crystal structure analysis of S.epidermidis adhesin SdrG binding to fibrinogen (adhesin-ligand complex)
In molecular biology, the protein domain SdrG C terminal refers to the C terminus domain of an adhesin found only on the cell walls of bacteria. More specifically, SdrG is only found in gram-positive bacteria. This particular domain binds to a glycoprotein named fibrinogen. SdrG stands for serine-aspartate dipeptide repeats, which as its name suggests, contains repeats of two amino acids, serine and aspartate.
Gram-positive pathogens such as Staphylococci, Streptococci, and Enterococci, contain SdrG anchored to their cell walls; these proteins act as adhesins and help the bacteria adhere to the host tissues via a dock-lock-latch mechanism. This protein domain is of huge significance since it binds to fibrinogen, a glycoprotein involved in important processes such as haemostasis and coagulation. By understanding more about the way they attach to human cells, it is hope a therapeutic target can be developed to preven diseases such as nosocomial sepsis which are caused by a bacterium which operates in this manner.
SdrG protein function
SdrG protein is a bacterial cell wall-anchored adhesion and its function is to adhere to human cells. It does this by binding to the Beta chain of human fibrinogen which is found in the extracellular matrix. Such adhesins have also been named MSCRAMMs which is short for microbial surface components recognizing adhesive matrix molecules.
SdrG C-terminal domain function
The C-terminal domain is responsible for the attachment of the protein to the attachment of the protein to the cell wall.
SdrG binds to its ligand with a dynamic "dock, lock, SdrG, the ligand binding site has been further localized and latch" mechanism. When it does bind to fibrinogen, it binds and forms an immunoglobin fold. SdrG as an apoprotein and in complex ligand binding activity peptide analogous to its binding site in Fg.
The whole SdrG protein contains two domains, a N-terminal one named N2 domain and the C-terminal one named N3.
C terminal domain structure
The C terminus contain a LPXTG sequence motif and hydrophobic amino acid segments attached to peptidoglycan. The C-terminal domain has many features which are required to fulfill its role: a proline-rich wall-spanning region, the wall-anchoring LPTXG motif, a hydrophobic transmembrane region and a cytoplasmic tail of positively charged amino acid residues. wo main beta sheets made up of four beta strands each arranged in to a beta-sandwich topology. The C-terminal part of SdrG(276-596) is integral to the folding of the immunoglobulin-like whole to create the docking grooves necessary for Fg binding.
Examples of proteins containing the SdrG C terminal domain
- McCrea KW, Hartford O, Davis S, Eidhin DN, Lina G, Speziale P et al. (2000). "The serine-aspartate repeat (Sdr) protein family in Staphylococcus epidermidis.". Microbiology 146 (7): 1535–46. PMID 10878118.
- Ponnuraj K, Bowden MG, Davis S, Gurusiddappa S, Moore D, Choe D et al. (2003). "A "dock, lock, and latch" structural model for a staphylococcal adhesin binding to fibrinogen.". Cell 115 (2): 217–28. doi:10.1016/S0092-8674(03)00809-2. PMID 14567919.
- Davis SL, Gurusiddappa S, McCrea KW, Perkins S, Höök M (2001). "SdrG, a fibrinogen-binding bacterial adhesin of the microbial surface components recognizing adhesive matrix molecules subfamily from Staphylococcus epidermidis, targets the thrombin cleavage site in the Bbeta chain.". J Biol Chem 276 (30): 27799–805. doi:10.1074/jbc.M103873200. PMID 11371571.
- Deivanayagam CC, Wann ER, Chen W, Carson M, Rajashankar KR, Höök M et al. (2002). "A novel variant of the immunoglobulin fold in surface adhesins of Staphylococcus aureus: crystal structure of the fibrinogen-binding MSCRAMM, clumping factor A.". EMBO J 21 (24): 6660–72. doi:10.1093/emboj/cdf619. PMC 139082. PMID 12485987.
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C-terminus of bacterial fibrinogen-binding adhesin Provide feedback
This is the C-terminal half of a bacterial fibrinogen-binding adhesin SdrG. SdrG is a Gram-positive cell-wall-anchored adhesin that allows attachment of the bacterium to host tissues via specific binding to the beta-chain of human fibrinogen (Fg). SdrG binds to its ligand with a dynamic "dock, lock, and latch" mechanism which represents a general mode of ligand-binding for structurally related cell wall-anchored proteins in most Gram-positive bacteria. The C-terminal part of SdrG(276-596) is integral to the folding of the immunoglobulin-like whole to create the docking grooves necessary for Fg binding. The domain is associated with families of Cna_B, PF05738 .
Ponnuraj K, Bowden MG, Davis S, Gurusiddappa S, Moore D, Choe D, Xu Y, Hook M, Narayana SV; , Cell. 2003;115:217-228.: A "dock, lock, and latch" structural model for a staphylococcal adhesin binding to fibrinogen. PUBMED:14567919 EPMC:14567919
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR011266
This entry represents the fibrinogen-binding domain from bacterial proteins such as fibrinogen-binding adhesion SdrG and clumping factor A. In both SdrG and clumping factor A, there are two fibrinogen-binding domains with similar core beta-sandwich topologies, but with different modulations in their structure. This entry represents the second domain, while INTERPRO represents the first domain.
Gram-positive pathogens, such as Staphylococci, Streptococci, and Enterococci, contain multiple cell wall-anchored proteins. Some of these proteins act as adhesins and mediate bacterial attachment to host tissues through lock-and-interactions with host ligands, such as fibrinogen, a glycoprotein found in blood plasma that plays a key role in haemostasis and coagulation. For pathogenic bacteria that do not invade host cells, extracellular matrix proteins are preferred targets for bacterial adhesion; adhesins mediating these interactions have been termed MSCRAMMs (microbial surface components recognizing adhesive matrix molecules). A common binding domain organisation found within MSCRAMMs suggests a common ancestry. Both fibrinogen-binding adhesion SdrG and clumping factor A are MSCRAMMs.
Fibrinogen-binding adhesion SdrG is a cell wall-anchored adhesion found in the Gram-positive pathogen Mycobacterium farcinogenes that binds to the B-beta chain of human fibrinogen [PUBMED:14567919]. SdrG allows attachment of the bacterium to host tissues via specific binding to the beta-chain of human fibrinogen (Fg). SdrG binds to its ligand with a dynamic "dock lock, and latch" mechanism which represents a general mode of ligand-binding for structurally related cell wall-anchored proteins in most Gram-positive bacteria. The C-terminal part of SdrG(276-596) is integral to the folding of the immunoglobulin-like whole to create the docking grooves necessary for Fg binding [PUBMED:14567919]. Clumping factor A performs a similar function in Staphylococcus aureus by binding the gamma chain of fibrinogen [PUBMED:12485987].
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Cellular component||cell wall (GO:0005618)|
|Biological process||cell adhesion (GO:0007155)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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Key: available, not generated, — not available.
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|Seed source:||Gene3D, pdb_1r17|
|Author:||Finn RD, Coggill PC|
|Number in seed:||35|
|Number in full:||1380|
|Average length of the domain:||161.70 aa|
|Average identity of full alignment:||27 %|
|Average coverage of the sequence by the domain:||17.80 %|
|HMM build commands:||
build method: hmmbuild -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||4|
|Download:||download the raw HMM for this family|
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There is 1 interaction for this family. More...
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For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the PDBe group, to allow us to map Pfam domains onto UniProt sequences and three-dimensional protein structures. The table below shows the structures on which the SdrG_C_C domain has been found. There are 14 instances of this domain found in the PDB. Note that there may be multiple copies of the domain in a single PDB structure, since many structures contain multiple copies of the same protein seqence.
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