3PF2: The Crystal Structure Of The Major Pilin Gbs80 Of Streptococcus Agalactiae 35kda C-Terminal Fragment

The Gram-positive pathogen Streptococcus agalactiae, known as group B Streptococcus (GBS), is the leading cause of bacterial septicemia, pneumonia, and meningitis among neonates. GBS assembles two types of pili-pilus islands (PIs) 1 and 2-on its surface to adhere to host cells and to initiate colonization for pathogenesis. The GBS PI-1 pilus is made of one major pilin, GBS80, which forms the pilus shaft, and two secondary pilins, GBS104 and GBS52, which are incorporated into the pilus at various places. We report here the crystal structure of the 35-kDa C-terminal fragment from GBS80, which is composed of two IgG-like domains (N2-N3). The structure was solved by single-wavelength anomalous dispersion using sodium-iodide-soaked crystals and diffraction data collected at the home source. The N2 domain exhibits a cnaA/DEv-IgG fold with two calcium-binding sites, while the N3 domain displays a cnaB/IgG-rev fold. We have built a model for full-length GBS80 (N1, N2, and N3) with the help of available homologous major pilin structures, and we propose a model for the GBS PI-1 pilus shaft. The N2 and N3 domains are arranged in tandem along the pilus shaft, whereas the respective N1 domain is tilted by approximately 20 degrees away from the pilus axis. We have also identified a pilin-like motif in the minor pilin GBS52, which might aid its incorporation at the pilus base.
PDB ID: 3PF2Download
MMDB ID: 88970
PDB Deposition Date: 2010/10/27
Updated in MMDB: 2011/05
Experimental Method:
x-ray diffraction
Resolution: 1.7  Å
Source Organism:
Similar Structures:
Biological Unit for 3PF2: monomeric; determined by author and by software (PISA)
Molecular Components in 3PF2
Label Count Molecule
Protein (1 molecule)
Cell Wall Surface Anchor Family Protein
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

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