Identification of genes encoding photoconvertible (Class I) water-soluble chlorophyll-binding proteins from <i>Chenopodium ficifolium</i>

Photoconvertible water-soluble chlorophyll-binding proteins, called Class I WSCPs, have been detected in Chenopodiaceae, Amaranthaceae and Polygonaceae plant species. To date, <i>Chenopodium album WSCP</i> (<i>CaWSCP</i>) is the only cloned gene encoding a Class I WSCP. In this study, we identified two cDNAs encoding <i>Chenopodium ficifolium</i> Class I WSCPs, <i>CfWSCP1</i>, and <i>CfWSCP2</i>. Sequence analyses revealed that the open reading frames of <i>CfWSCP1</i> and <i>CfWSCP2</i> were 585 and 588 bp, respectively. Furthermore, both CfWSCPs contain cystein2 and cystein30, which are essential for the chlorophyll-binding ability of CaWSCP. Recombinant CfWSCP1 and CfWSCP2, expressed in <i>Escherichia coli</i> as hexa-histidine fusion proteins (CfWSCP1-His and CfWSCP2-His), formed inclusion bodies; however, we were able to solubilize these using a buffer containing 8 M urea and then refold them by dialysis. The refolded CfWSCP1-His and CfWSCP2-His could bind chlorophylls and exhibited photoconvertibility, confirming that the cloned CfWSCPs are further examples of Class I WSCPs.