Mayuko Ono, Shigekazu Takahashi, Risa Shibata, Mizuki Tomizawa, Katsumi Nakayama and Hiroyuki Satoh
Non-photoconvertible water-soluble chlorophyll-binding proteins, called Class II WSCPs, have been identified in some Brassicaceae plants. Although the WSCP in black mustard (Brassica nigra) was the second Class II WSCP to be reported by Murata and Murata, the cDNA has not been cloned until now. In this study, we cloned a cDNA encoding the black mustard WSCP (BmWSCP) and analyzed its chlorophyll binding affinity using its recombinantly expressed protein. Sequence analyses revealed that the mature region the BmWSCP cDNA was predicted to be 534 bp encoding a protein of 178 amino acid residues. Recombinant BmWSCP was expressed in Escherichia coli as a hexa-histidine fusion protein and could bind successfully to chlorophylls, with its highest affinity to Chl a, confirming that the cDNA encodes a Class IIA WSCP in black mustard.