This superfamily contains domain I of Cypl (extracytoplasmic thiamine-binding lipoprotein). Literature suggests that the high affinity transport system protein p37 specific to Mycoplasma species (as it currently appears in pfam and InterPro entries) was renamed the extracytoplasmic thiamine-binding lipoprotein. The p37 gene is part of an operon encoding two additional proteins which are highly similar to components of the periplasmic binding-protein-dependent transport systems of Gram-negative bacteria. It has been suggested that p37 is part of a homologous, high-affinity transport system in M. hyorhinis, a Gram-positive bacterium. Its structure indicates that it is a thiamine pyrophosphate-binding protein.

The monomer is a mixed alpha/beta fold split into two globular domains (Domains I and II) connected by two linker regions and the C-terminal helix. This entry represents Domain I, which consists of a six-stranded beta-sheet flanked by seven helices.

PFAM:PF06646, INTERPRO:IPR010592,DOI:10.1128/JB.01680-08,DOI:10.1002/prot.22900