7VCN

Crystal Structure of PitA fragment from pilus islet-2 of Streptococcus oralis with Tb-Xo4

Summary for 7VCN

• Entry DOI: 10.2210/pdb7vcn/pdb
• Descriptor: von Willebrand factor type A domain protein, Tb-Xo4, TERBIUM(III) ION, ... (5 entities in total)
• Functional Keywords: tip pilin, adhesin, pita; pi-2 pilus; streptococcus oralis, isopeptide, cnaa fold, cnab fold, cell adhesion, crystallophore, terbium, biofilm, dental plaque
• Biological source: Streptococcus oralis ATCC 35037; More
• Total number of polymer chains: 4
• Total formula weight: 112660.33

Authors

Yadav, R.K.,Krishnan, V. (deposition date: 2021-09-03, release date: 2022-07-13, Last modification date: 2024-05-29)

Primary citation

Yadav, R.K.,Krishnan, V.
New structural insights into the PI-2 pilus from Streptococcus oralis, an early dental plaque colonizer.
Febs J., 289:6342-6366, 2022

PubMed Abstract: Streptococcus oralis is a member of the mitis group of oral streptococci and an early colonizer in dental plaque biofilm, a major cause of periodontal disease, dental caries, and other oral infections. S. oralis promotes biofilm growth by coaggregating in a mutualistic partnership with other early colonizers such as Actinomyces oris. For this cell-to-cell interaction, A. oris is known to use its sortase-dependent pilus (type 2), but whether S. oralis uses its PI-2 (pilus islet 2) pilus is still to be determined. The PI-2 pilus is predicted to have a heterodimeric structure consisting of two different protein subunits with their own location and function: the tip PitA pilin for adhesion and the backbone PitB pilin for length. Thus far, structural information remains incomplete about the role of PI-2 pili in the mutualistic mechanism between S. oralis and A. oris. We now report on the crystal structure analysis of PitA and PitB using X-ray crystallography, small-angle X-ray scattering, and molecular docking studies. Accordingly, we propose a structural model for the PI-2 pilus, wherein repeating PitB subunits are arranged head-to-tail to form the long backbone structure with PitA on the outer tip. By performing both in vitro and in vivo experiments, we examined the role played by PitA in mediating the mutualistic interaction between S. oralis and A. oris, which appears to involve the coaggregation factor CafA. We also reveal that the galactose monosaccharide is a conceivable ligand for PitA and thereby might be used to inhibit coaggregation and control oral biofilm development. DATABASE: Structural coordinates for the PitA fragment, PitA fragment TbXO4 derivative, full-length PitA, and PitB from S. oralis have been deposited at the Protein Data Bank as 7VCR, 7W7I, 7VCN, 7W6B, and 7W7I, respectively. Streptococcus pneumoniae PitB coordinates have been deposited as 7F7Y.

PubMed: 35561142
DOI: 10.1111/febs.16527

Experimental method

X-RAY DIFFRACTION (2.343 Å)