Reentrant region motif derived from fragments of size 8 from protein belonging to different families. The motif has been found to be a cross-family pattern, found mainly, in this study, in both subunits of voltage gated chloride channels (Pfam: PF00654), in 24.4 % of the cases), but also in other proteins like ammonium transporters (Pfam: PF00909), multidrug resistant protein mdtK (Pfam: PF01554), subunit III of photosystem I reaction center (Pfam: PF02507), glycoproteins. For a complete list of clans see below.

Structural description: The motif shows the conserved regular alpha-helix hydrogen bond pattern i, i+4, with a lack of a helical-turn hydrogen bond between main chain atoms in positions 2 and 6, that would otherwise ensure the continuity of the alpha-helix. The backbone torsion angle pattern associated to the motif is illustrated below.

Functional annotation: The motif hits 82 transmembrane proteins in the Swiss-Prot database. The Swiss-Prot ids of the proteins carrying the motif are listed below. There are no significant GO terms associated with the motif.

In chloride channels the motif is located, in sequence, just after the A-[AS]-[FIV]-[NR]-A-P-L-[AT]-G motif and it is part of the same reentrant region described to be at the dimmer interface. Unlike the A-[AS]-[FIV]-[NR]-A-P-L-[AT]-G motif, which is specific to the voltage gated chloride channel family (Pfam: PF00654), the L-[AT]-G-[FI]-[AILV]-x-[IPV]-[IL] motif has been found across 13 different Pfam clans, meaning that this structural motif, which is a combination of small and hydrophobic amino acids, is typical to reentrant regions. In photosystem I (pdb id: 1jb0, chain F), the complex that mediates light-driven transmembrane electron transfer from plastocyanin to ferrodoxin in eukaryotic and cyanobacterial photosynthesis, the motif is found in the small subunit III, which is thought to anchor this subunit to the reaction center core (PMID: 8486290). The function of this subunit and the specific role of the reentrant motif are not yet fully understood (PMID: 8434435).