Isolation and characterization of a salt-induced PsaG of photosystem I in Dunaliella salina.
Some cDNA sequences of subunit V (PsaG) of Photosystem I (PS I) reaction center in several species have been cloned, and PsaG has been characterized as a connection of light-harvesting complex I (LHC I) protein to photosystem reaction center. Here we present the isolation and characterization of its salt-induced homologue (DsPsaG) in Dunaliella salina. Sequence alignment shows that there is a significant similarity between the deduced amino acid sequence of DsPsaG and PsaG protein in Chlamydomonas reinhardtii, as well as between the deduced amino acid sequence of DsPsaG and other PsaG gene products. The differential expression of DsPsaG at different time points after salt stress reveals that DsPsaG mRNA was absent without salt stress and was indeed salt-induced. Its expression reached its maximum level 5 days after stress. Our study suggests that DsPsaG should be a compensation of PsaG in D. salina when the alga was in a hyperosmotic condition. It can also be useful to effectively transfer light energy from LHC I to PS I reaction center.
Zhang
Xiao-Ning
XN
Institute of Genetics, State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan Research Centre of Gene Diversity and Designed Agriculture, Fudan University, Shanghai, People's Republic of China.
Lin
Chang-Fa
CF
Zhang
Hong-Wei
HW
Shen
Da-Leng
DL
D000595:Amino Acid Sequence; D001483:Base Sequence; D000460:Chlorophyta / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics* / Q000378:metabolism; D045331:Photosystem I Protein Complex; D016415:Sequence Alignment; D012965:Sodium Chloride / Q000378:metabolism
D045322:Photosynthetic Reaction Center Complex Proteins; D045331:Photosystem I Protein Complex; D012965:Sodium Chloride