Anion-selective Formate/nitrite transporters: taxonomic distribution, phylogenetic analysis and subfamily-specific conservation pattern in prokaryotes

Table 7 FNT channels with unique central constriction region

FNT subfamily	UniProt ID^a (Organism)	Central constriction residues^b	CHI/CVV value^c
Unclassified	Q1Q4Z9 (Candidatus Kuenenia stuttgartiensis)	YFQS	CHI: −2.8
YfdC-α	Q0G7B8 (Fulvimarina pelagi)	YLHT	CHI: −1.4
YfdC-α	Q1YI18 (Aurantimonas manganoxydans)	YVHT	CHI: −1.0
YfdC-α	I1ARB3 (Citreicella sp.)	YMHA	CHI: −0.8
YfdC-β	K9AG69 (Brevibacterium casei)	FVHI	CHI: +8.3
Unclassified	Q1PZF5 (Candidatus Kuenenia stuttgartiensis)	FIHV	CHI: +8.3
NirC-γ	B9DL87, B9DLT5 (Staphylococcus carnosus) B9E993 (Macrococcus caseolyticus) E8SEZ7 (Staphylococcus pseudintermedius) E8SFH6 (Staphylococcus pseudintermedius) G5JLA8 (Staphylococcus simiae) I7JE48 (Staphylococcus equorum) K9AHL1, K9ANW4 (Staphylococcus massiliensis) J9HA25 (Staphylococcus sp.) and 6 more	FFHY	CVV: 529 Ǻ³

^aThe unique UniProt Accession ID is given
^bThe four residues that form central constriction site within the channel. They correspond to F75 from TM2a, F202 from TM5a, H209 from S-loop and A212 from TM5b of the formate channel (PDB ID: 3KCU)
^cCalculation of Cumulative Hydropathy Index (CHI) and Cumulative vdw Volume (CVV) are described in the text

ISSN: 1471-2164