The PAS fold corresponds to the structural domain that has previously been defined as PAS and PAC motifs [4]. The PAS fold appears in archaea, eubacteria and eukarya. This domain is associated to signalling systems and works as a signal sensor domain. It recognises differently substituted aromatic hydrocarbons, oxygen, different dodecanoic acids, autoinducers, 3,5-dimethyl-pyrazin-2-ol and N-alanyl-aminoacetone (Matilla et. al., FEMS Microbiology Reviews, fuab043, 45, 2021, 1. https://doi.org/10.1093/femsre/fuab043).

1: PAS domain S-boxes in archaea, bacteria and sensors for oxygen and redox. Zhulin IB, Taylor BL, Dixon R; Trends Biochem Sci 1997;22:331-333. PMID:9301332

2: 1.4 A structure of photoactive yellow protein, a cytosolic photoreceptor: unusual fold, active site, and chromophore. Borgstahl GE, Williams DR, Getzoff ED; Biochemistry 1995;34:6278-6287. PMID:7756254

3: PAS: a multifunctional domain family comes to light. Ponting CP, Aravind L; Curr Biol 1997;7:674-677. PMID:9382818

4: The PAS fold: a redefination of the PAS domain based upon structural prediction. Hefti MH, Francoijs KJ, de Vries SC, Dixon R, Vervoort J; Eur J Biochem 2004;271:1198-1208. PMID:15009198