This domain, approximately 140 residues in length, is mainly found in general stress proteins in various Xanthomonas species. It is composed of a six-stranded antiparallel beta-barrel flanked by five alpha-helices and can bind to FMN and FAD, suggesting that it may help the bacteria to react against the oxidative stress induced by the defense mechanisms of the plant [1].

1: The structure of a Xanthomonas general stress protein involved in citrus canker reveals its flavin-binding property. Hilario E, Li Y, Niks D and Fan L; Acta Crystallogr. D Biol. Crystallogr. 2012;68(7):846-853. PMID:22751670