CLONING, SUBCELLULAR-LOCALIZATION AND EXPRESSION OF CHLI, A SUBUNIT OF MAGNESIUM-CHELATASE IN SOYBEAN

Mg-insertion is the first committed step in chlorophyll synthesis and is catalyzed by Mg-chelatase. In photosynthetic bacteria, bchI gene pr oduct was suggested to be a subunit of Mg-chelatase. We isolated a bch I homolog from a soybean cDNA library and designated it as chlI. CHLI consisted of 421 amino acid residues and the sequence exhibited a high similarity to other BchI homologs. CHLI contained an ATP-binding moti f found in other BchI homologs. CHLI was localized in the soluble frac tion in soybean chloroplasts, suggesting that it was stromal subunit o f Mg-chelatase. chlI mRNA in cell culture (SB-P) of soybean was revers ibly induced by light. (C) 1995 Academic Press. Inc.