Mapping and sequencing of an actively transcribed <i>Euglena gracilis</i> chloroplast gene (<i>ccs</i>A) homologous to the <i>Arabidopsis thaliana</i> nuclear gene <i>cs(ch-42)</i>

We mapped and sequenced a novel chloroplast gene encoding a protein (348 amino acids) which shows a high sequence identity with both the decoded nuclear <i>cs(ch-42)</i> gene product of <i>Arabidopsis thaliana</i>, and the C-terminal half of the decoded ‘<i>crt</i>A’ gene product of <i>Rhodobacter capsulatus</i>. The chloroplast gene (ccsA) is split (two exons) and transcribed into a stable mRNA of about 1200 nucleotides. The putative protein may be involved in the biosynthesis of photosynthetic pigments.