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.