Identification and functional analysis of a novel parvulin-type peptidyl-prolyl isomerase from Gossypium hirsutum.
Plants have developed a variety of adaptive mechanisms to cope with stresses. A novel salt-induced gene was isolated during the screening of a NaCl-induced cDNA library of cotton seedlings. The gene was registered as accession number AY972810 in GenBank. Phylogenetic analysis suggested that the protein encoded by the gene belongs to the parvulin family of peptidyl-prolyl cis/trans isomerases (PPIases, EC 5.2.1.8). Northern blot analysis indicated that the mRNA accumulation of GhPPI was induced by salt stress. Subcellular localization revealed that GhPPI (Gossypium hirsutum peptidyl-prolyl isomerase) was localized in the nucleus. The purified recombinant GhPPI could accelerate the initial velocity of the cis-trans conversion of peptidyl-prolyl bonds of a tetrapeptide in a GhPPI concentration-dependent manner. Recombinant GhPPI also suppressed protein aggregation under denaturing conditions using Gdn-HCl (guanidine hydrochloride), suggesting an additional chaperone activity. Several amino acid residues in GhPPI were speculated to be involved in substrate binding or catalysis based on molecular modeling and docking results. The activity of the peptidyl-prolyl isomerase was affected when the relevant amino acids were mutated. Among the 11 mutants, five amino acids mutations led to the enzyme activities decreased to 30% as that of wild type, and two reduced to approximately 60%. To the best of our knowledge, this is the first report of a plant parvulin PPIase involved in the salt stress response.
College of Life Science, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China.
Ping
P
Wang
College of Life Science, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China.
Xin-Zheng
XZ
Li
College of Life Science, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China.
Hao-Ran
HR
Cui
Jinan Academy of Agricultural Sciences, Shandong, Jinan 250300, People's Republic of China.
Yue-guang
YG
Feng
College of Life Science, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China; State Key Laboratory of Crop Biology, Shandong Agricultural University, Shandong, Taian 271018, People's Republic of China. Electronic address: xyunwang@sdau.edu.cn.
Xiao-Yun
XY
Wang
D000595:Amino Acid Sequence; D002467:Cell Nucleus / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D015723:Gene Library; D003368:Gossypium / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D018832:Molecular Chaperones / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D017510:Protein Folding; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride / Q000737:chemistry
D018076:DNA, Complementary; D018832:Molecular Chaperones; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D010940:Plant Proteins; D012965:Sodium Chloride; D019696:Peptidylprolyl Isomerase
Gossypium hirsutum; Key amino acids; PPIase; Salt stress