5FGS

Crystal structure of C-terminal domain of shaft pilin spaA from Lactobacillus rhamnosus GG - P21212 space group

Summary for 5FGS

• Entry DOI: 10.2210/pdb5fgs/pdb
• Related: 5F44 5FAA 5FGR 5FIE 5HBB 5HDL 5HTS 5J4M
• Descriptor: Cell surface protein SpaA, ZINC ION (3 entities in total)
• Functional Keywords: pilin, spaa, probiotic, isopeptide, spacba pili, adhesin, cell adhesion
• Biological source: Lactobacillus rhamnosus GG
• Total number of polymer chains: 4
• Total formula weight: 59812.91

Authors

Chaurasia, P.,Pratap, S.,von Ossowski, I.,Palva, A.,Krishnan, V. (deposition date: 2015-12-21, release date: 2016-07-20, Last modification date: 2023-11-08)

Primary citation

Chaurasia, P.,Pratap, S.,von Ossowski, I.,Palva, A.,Krishnan, V.
New insights about pilus formation in gut-adapted Lactobacillus rhamnosus GG from the crystal structure of the SpaA backbone-pilin subunit
Sci Rep, 6:28664-28664, 2016

PubMed Abstract: Thus far, all solved structures of pilin-proteins comprising sortase-assembled pili are from pathogenic genera and species. Here, we present the first crystal structure of a pilin subunit (SpaA) from a non-pathogen host (Lactobacillus rhamnosus GG). SpaA consists of two tandem CnaB-type domains, each with an isopeptide bond and E-box motif. Intriguingly, while the isopeptide bond in the N-terminal domain forms between lysine and asparagine, the one in the C-terminal domain atypically involves aspartate. We also solved crystal structures of mutant proteins where residues implicated in forming isopeptide bonds were replaced. Expectedly, the E-box-substituted E139A mutant lacks an isopeptide bond in the N-terminal domain. However, the C-terminal E269A substitution gave two structures; one of both domains with their isopeptide bonds present, and another of only the N-terminal domain, but with an unformed isopeptide bond and significant conformational changes. This latter crystal structure has never been observed for any other Gram-positive pilin. Notably, the C-terminal isopeptide bond still forms in D295N-substituted SpaA, irrespective of E269 being present or absent. Although E-box mutations affect SpaA proteolytic and thermal stability, a cumulative effect perturbing normal pilus polymerization was unobserved. A model showing the polymerized arrangement of SpaA within the SpaCBA pilus is proposed.

PubMed: 27349405
DOI: 10.1038/srep28664

Experimental method

X-RAY DIFFRACTION (2 Å)