6M48

Crystal structure of pilus adhesin, SpaC from Lactobacillus rhamnosus GG - P21212 form

Summary for 6M48

• Entry DOI: 10.2210/pdb6m48/pdb
• Related: 6M3Y
• Descriptor: SpaC, MAGNESIUM ION, CHLORIDE ION, ... (4 entities in total)
• Functional Keywords: pilus adhesin, tip pilin, vwfa domain, spacba pilus, sortase, lactobacillus rhamnosus gg, pili, fimbria, probiotics, spac, lectin, surface protein, cell adhesion, midas
• Biological source: Lactobacillus rhamnosus GG
• Total number of polymer chains: 2
• Total formula weight: 181992.25

Authors

Kant, A.,Palva, A.,Von Ossowaski, I.,Krishnan, V. (deposition date: 2020-03-05, release date: 2020-07-29, Last modification date: 2024-11-06)

Primary citation

Kant, A.,Palva, A.,von Ossowski, I.,Krishnan, V.
Crystal structure of lactobacillar SpaC reveals an atypical five-domain pilus tip adhesin: Exposing its substrate-binding and assembly in SpaCBA pili.
J.Struct.Biol., 211:107571-107571, 2020

PubMed Abstract: Adhesion to cell surfaces is an essential and early prerequisite for successful host colonization by bacteria, and in most instances involves the specificities of various adhesins. Among bacterial Gram-positives, some genera and species mediate attachment to host cells by using long non-flagellar appendages called sortase-dependent pili. A case in point is the beneficial Lactobacillus rhamnosus GG gut-adapted strain that produces the so-called SpaCBA pilus, a structure noted for its promiscuous binding to intestinal mucus and collagen. Structurally, SpaCBA pili are heteropolymers of three different pilin-protein subunits, each with its own location and function in the pilus: backbone SpaA for length, basal SpaB for anchoring, and tip SpaC for adhesion. Previously, we solved the SpaA tertiary structure by X-ray crystallography and also reported on the crystallization of SpaB and SpaC. Here, we reveal the full-length high-resolution (1.9 Å) crystal structure of SpaC, a first for a sortase-dependent pilus-bearing commensal. The SpaC structure, unlike the representative four-domain architecture of other Gram-positive tip pilins, espouses an atypically longer five-domain arrangement that includes N-terminal 'binding' and C-terminal 'stalk' regions of two and three domains, respectively. With the prospect of establishing new mechanistic insights, we provide a structural basis for the multi-substrate binding nature of SpaC, as well as a structural model that reconciles its exclusive localization at the SpaCBA pilus tip.

PubMed: 32653644
DOI: 10.1016/j.jsb.2020.107571

Experimental method

X-RAY DIFFRACTION (2.5 Å)