Are tyrosine residues involved in the photoconversion of the water‐soluble chlorophyll‐binding protein of Chenopodium album?. (8th January 2015)

• Record Type: Journal Article
• Authors: Takahashi, S.; Seki, Y.; Uchida, A.; Nakayama, K.; Satoh, H.; Sugita, M.
• Is Part Of: Plant biology. Volume 17:Number 3(2015:May)
• Page Start: 632
• Page End: 638
• Publication Date: 2015-01-08
• Subjects: Botany -- Periodicals; Plants -- genetics -- Periodicals; Plants -- growth & development -- Periodicals; Plant Proteins -- Periodicals; Gene Expression Regulation, Plant -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1111/plb.12274
• Languages: English
• ISSNs: 1435-8603

Abstract

<abstract abstract-type="main" id="plb12274-abs-0001"> <title>Abstract</title> <p>Non‐photosynthetic and hydrophilic chlorophyll (Chl) proteins, called water‐soluble Chl‐binding proteins (WSCPs), are distributed in various species of Chenopodiaceae, Amaranthaceae, Polygonaceae and Brassicaceae. Based on their photoconvertibility, WSCPs are categorised into two classes: Class I (photoconvertible) and Class II (non‐photoconvertible). <italic>Chenopodium album </italic>WSCP (CaWSCP; Class I) is able to convert the chlorin skeleton of Chl <italic>a</italic> into a bacteriochlorin‐like skeleton under light in the presence of molecular oxygen. Potassium iodide (KI) is a strong inhibitor of the photoconversion. Because KI attacks tyrosine residues in proteins, tyrosine residues in CaWSCP are considered to be important amino acid residues for the photoconversion. Recently, we identified the gene encoding CaWSCP and found that the mature region of CaWSCP contained four tyrosine residues: Tyr13, Tyr14, Tyr87 and Tyr134. To gain insight into the effect of the tyrosine residues on the photoconversion, we constructed 15 mutant proteins (Y13A, Y14A, Y87A, Y134A, Y13‐14A, Y13‐87A, Y13‐134A, Y14‐87A, Y14‐134A, Y87‐134A, Y13‐14‐87A, Y13‐14‐134A, Y13‐87‐134A, Y14‐87‐134A and Y13‐14‐87‐134A) using site‐directed mutagenesis. Amazingly, all the mutant proteins retained not only chlorophyll‐binding activity, but also photoconvertibility. Furthermore, we found that KI strongly inhibited the photoconversion of Y13‐14‐87‐134A. These findings indicated that the four tyrosine residues are not essential for the photoconversion.</p> </abstract>