Abstract：Abstract：Aquaporins are water channel proteins belonging to the major intrinsic protein (MIP) superfamily of membrane proteins. Plant aquaporins play an important role in response to water balance, since their discovery, advancing knowledge of their structure led to an understanding of the basic features of the water transport mechanism. In the present study, the gene encoding the Solarium tuberosum L. aquaporin (StPIP1) cDNA was isolated from leaf of “GannongShu No.2” under PEG6000 stress by reverse transcription-polymerase chain reaction(RT-PCR ), the analysis of the sequence showed that StPIP1 cDNA was 867-bp in length , the protein encoded by 288 amino acids with a predicted molecular mass of 30. 9KD; StPIP1 exhibited six predicted transmembrane helices and possesses two sets of conserved NPA motifs as well as the highly conserved motifs on M1 and M4 as EXXXTXXF/L which may be involved in the recognition and transport of water molecules across the water channel, and possessing the MIP family signal consensus sequence SGXHXNPAVT and the higher plant PIP highly conservative sequence GGGANXXXXGY and TGI/TNPARSL/FGAAI/VI/VF/YN. As compared to PIP1 identified from other 14 plant species PIP1 subfamily by phylogenetic trees, StPIP1 has the highly sequence identity at the amino acids level (more than 92%), so StPIP1 should be a member of PIP1 subfamily. The protein 3D structure was predicted by homology comparatvie modeling in Swiss-Model, the results feedback from Swiss-model showed that the 3D structure of StPIP1was highly similitude with spinach(2B5F).
