Characterization Of ChlG And BchG From Green Sulfur Bacterium Chlorobium tepidum By Heterologus Gene Expression.

Abstract

Biosynthetic pathways of chlorophyll (Chl) a and bacteriochlorophyll (BChl) a are common from protoporphyrin IX to chlorophyllide (Chlide) a. Chl a is synthesized from Chlide a by ChlG, while BChl a is synthesized from BChlide a by BchG. Green sulfur bacterium Chlorobium tepidum synthesis three kinds of chlorophylls, BChl a, Chl a, and BChl c. In the genome of C. tepidum, three homologues of chlG/bchG (CT1270, CT1610 and CT1992 ) are found. In this study, we introduced CT1270 and CT1610 to strains of purple bacterium Rhodobacter capsulatus, which were knockouted BChl a biosynthesis genes. We observed that novel pigments were accumulated in the CT1270-introduced cell. We also found that a single pigment component which has a same retention time of Chl a was eluted by HPLC. It was revealed that this pigment has the same molecular mass as phytyl-Chl a by LC-Mass analysis.