4K8W
An arm-swapped dimer of the S. pyogenes pilin specific assembly factor SipA
Summary for 4K8W
| Entry DOI | 10.2210/pdb4k8w/pdb |
| Descriptor | LepA, 1,2-ETHANEDIOL, ETHANOL, ... (4 entities in total) |
| Functional Keywords | predominately beta-strand, s26a signal peptidase family, pilin assembly, extracellular membrane bound, cell adhesion |
| Biological source | Streptococcus pyogenes |
| Total number of polymer chains | 1 |
| Total formula weight | 14745.55 |
| Authors | Young, P.G.,Kang, H.J.,Baker, E.N. (deposition date: 2013-04-19, release date: 2013-06-26, Last modification date: 2024-02-28) |
| Primary citation | Young, P.G.,Kang, H.J.,Baker, E.N. An arm-swapped dimer of the Streptococcus pyogenes pilin specific assembly factor SipA. J.Struct.Biol., 183:99-104, 2013 Cited by PubMed Abstract: Streptococcus pyogenes (group A streptococcus [GAS]) is a major human pathogen. Attachment of GAS to host cells depends in large part on pili. These assemblies are built from multiple covalently linked subunits of a backbone protein (FctA), which forms the shaft of the pilus, and two minor pilin proteins, FctB anchoring the pilus to the cell wall and Cpa functioning as the adhesin at the tip. Polymerisation of the pilin subunits is mediated by a specific sortase, which catalyzes the formation of peptide bonds linking successive subunits. An additional gene, SipA, is also essential for GAS pilus polymerisation, but its function remains undefined. Here we report the crystal structure of a truncated SipA protein from GAS, determined at 1.67Å resolution. The structure reveals that SipA has the same core fold as the Escherichia coli type-I signal peptidase (SPase-I), but has a much smaller non-catalytic domain. The truncated protein, which lacks 9 N-terminal residues, forms an arm-swapped dimer in which the C-terminal β-strand of each monomer crosses over to interact with an N-terminal strand from the other monomer. In addition, there is no peptide binding cleft and significant differences in the putative membrane association region. PubMed: 23747392DOI: 10.1016/j.jsb.2013.05.021 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.67 Å) |
Structure validation
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