Table 2.

Aromatic/arginine selectivity filter residues and substitutions in the conserved NPA motifs in plant subfamilies TIPs and SIPs

		Aromatic/arginine selectivity filter c
Plant MIP subfamily a	Number of sequences/Total number of sequences b	TM2	TM5	LE1	LE2	NPA substitutions (%) d
TIPse	90/181	H	I/V/M	A/G/S	R	1.1
	65/181	H	I/V	A	V/L/I
	16/181	H/Q/N	T/S/A	A	R
	5/181	Q	V	A	R
	3/181	H	V	G	C
SIPsf	13/25	V/F/I/L	V/I	P	N	84.0
	6/25	S/T/Y	H	G	S/A
	3/25	I/V	V/F	P	I/F
	3/25	A/S	V	P	N

^aFor details of different plant MIP subfamilies, see [10]–[12].

^bNumber of sequences possessing a particular type of Ar/R selectivity filter residues and the total number of sequences belonging to TIPs or SIPs are given.

^cSee foot note c of Table 1.

^dPercentage of sequences from TIPs or SIPs that have substitution(s) in at least one of the conserved NPA motifs.

^eTIP sequences belong to the following plants:

Daucus carota, Oryza sativa, Gossypium hirsutum, Kandelia candel, Poa pratensis, Nicotiana glauca, Medicago sativa, Brachypodium distachyon, Brassica napus, Hordeum vulgare, Lolium perenne, Triticum aestivum, Mesembryanthemum crystallinum, Wolffia australiana, Glycine max, Sporobolus stapfianus, Solanum lycopersicum, Solanum tuberosum, Lilium longiflorum, Spinacia oleracea, Pisum sativum, Dendrobium officinale, Sorghum bicolor, Arabidopsis thaliana, Zea mays, Cucurbita cv. Kurokawa Amakuri, Antirrhinum majus, Vitis vinifera, Lycopersicon esculentum, Raphanus sativus, Petroselinum crispum, Populus trichocarpa, Brassica oleracea, Helianthus annuus, Posidonia oceanic, Pyrus communis, Setaria italic, Petunia hybrid, Medicago truncatula, Vernicia fordii, Vitis berlandieri x Vitis rupestris, Nicotiana tabacum, Tulipa gesneriana, Lotus japonicas, Phaseolus vulgaris.

^fPlant SIP sequences have been identified in the following species:

Brachypodium distachyon, Sorghum bicolor, Oryza sativa, Zea mays, Setaria italic, Triticum aestivum, Arabidopsis thaliana, Solanum tuberosum, Solanum lycopersicum, Populus trichocarpa.