Molecular Characterization of LRB7 Gene and a Water Channel Protein TIP2 in Chorispora bungeana

Figure 2

Structures and phylogenetic analysis of LRB7 gene and TIP2. (a) Gene structure of LRB7 showed that two introns can be identified. (b) Both intron-1 and intron-2 satisfied the GT/AG splicing rule. (c) Alignment of deduced amino acid sequence of LRB7 and other 8 TIPs showed two conserved NPA motifs (loop b and loop e) of which loop b was proved to be MIP signature sequence (SGxHxNPAVT), N-glycosylation site (first black triangle arrow), and mercury-sensitive site (cysteine residue, second black triangle arrow). The TIPs are from Arabidopsis thaliana (X72581, AF057137, and U39485), Raphanus sativus (D84669 and AB010416), Pyrus communis (AB048248), Triticum aestivum (U86762), Chorispora bungeana (EU636988), and Nicotiana glauca (AB010416). Using TMHMM-2.0, we predicted six transmembrane helix regions (M1 to M6, underlined) in the protein of LRB7. Its topography in the vacuolar membrane (d) showed high consistence with the model drawn by Daniels et al. [20]. (e) Phylogenetic analysis of 29 TIP sequences told us that the protein encoded by LRB7 in C. bungeana was TIP2 (in red).

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