Abstract
BackgroundAtCYP38, a thylakoid lumen localized immunophilin, is essential for photosystem II (PSII) assembly and maintenance, but how AtCYP38 functions in chloroplast remains unknown. Based on previous functional studies and its crystal structure, we hypothesize that AtCYP38 should function via binding its targets or cofactors in the thylakoid lumen to influence PSII performance. Therefore, identifying its target proteins and cofactors would be a key step to understand the working mechanism of AtCYP38.ResultsTo identify potential interacting proteins of AtCYP38, we first adopted two web-based tools, ATTED-II and STRING, and found 15 proteins functionally related to AtCYP38. We then screened a yeast two-hybrid library including an Arabidopsis genome wide cDNA with the N-terminal domain, the C-terminal domain, and the full-length mature protein of AtCYP38. 25 positive targets were identified, but a very limited number of target proteins were localized in the thylakoid lumen. In order to specifically search interacting proteins of AtCYP38 in the thylakoid lumen, we created a yeast two-hybrid mini library including the thylakoid lumenal proteins and lumen fractions of thylakoid membrane proteins. After screening the mini library with 3 different forms of AtCYP38, we obtained 6 thylakoid membrane proteins and 9 thylakoid lumenal proteins as interacting proteins of AtCYP38. We further confirmed the localization of several identified proteins and their interaction between AtCYP38.ConclusionsAfter analysis with two web-based tools and yeast two-hybrid screenings against two different libraries, we identified a couple of potential interacting proteins, which could be functionally related to AtCYP38. We believe that the results will lay a foundation for unveiling the working mechanism of AtCYP38 in photosynthesis.
CapsID: a web-based tool for developing parsimonious sets of CAPS molecular markers for genotyping
