From genome to function: the Arabidopsis aquaporins

Table 4 Consensus residues distinguishing AQPs and GLP proteins

Consensus position*	P1 after H3	P2 at NPA-LB	P3 after H5	P4 at NPA-LE	P5 at NPA-LE	NPA-LB	NPA-LE
AQP-type	T/Q/M/E/V/A	S/A	A	Y/F	W
GLP-type	Y/F	D	R/K	P/A	I/V/L/M/A/W
Arabidopsis AQP family
PIP	Q	S	A	F	W	NPA	NPA
TIP	T/V	S/A	A	Y	W	NPA	NPA
NIP	F/Y	S/T	A	Y	I/L/M	NPA/S	NPA/G/V
SIP	I/F	A/V	A	Y	W	NPT/C/L	NPA
Character†
AQP-like	PIP, TIP	PIP, TIP, NIP, SIP	PIP, TIP, NIP, SIP	PIP, TIP, NIP, SIP	PIP, TIP, SIP
GLP-like	NIP, SIP	-	-	-	NIP

H, transmembrane domain. NPA-LB/NPA-LE, first and second NPA motif, respectively. P1-P5, conserved residues that may distinguish functions. *According to [58]. †Most Arabidopsis sequences resemble true AQPs; subfamily NIP shows some characteristics of glycerol facilitators.

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