This is a Ig-like domain found in Streptococcus agalactiae tip pilin GBS104 and similar proteins [1-4].

1: Structural basis of host cell recognition by the pilus adhesin from Streptococcus pneumoniae. Izore T, Contreras-Martel C, El Mortaji L, Manzano C, Terrasse R, Vernet T, Di Guilmi AM, Dessen A; Structure. 2010;18:106-115. PMID:20152157

2: Structure of Streptococcus agalactiae tip pilin GBS104: a model for GBS pili assembly and host interactions. Krishnan V, Dwivedi P, Kim BJ, Samal A, Macon K, Ma X, Mishra A, Doran KS, Ton-That H, Narayana SV; Acta Crystallogr D Biol Crystallogr. 2013;69:1073-1089. PMID:23695252

3: Autocatalytic association of proteins by covalent bond formation: a Bio Molecular Welding toolbox derived from a bacterial adhesin. Bonnet J, Cartannaz J, Tourcier G, Contreras-Martel C, Kleman JP, Morlot C, Vernet T, Di Guilmi AM; Sci Rep. 2017;7:43564. PMID:28252635

4: Crystal structure of lactobacillar SpaC reveals an atypical five-domain pilus tip adhesin: Exposing its substrate-binding and assembly in SpaCBA pili. Kant A, Palva A, von Ossowski I, Krishnan V; J Struct Biol. 2020;211:107571. PMID:32653644