This enzyme, found in green sulfur bacteria (Chlorobiaceae) and green filamentous bacteria (Chloroflexaceae), catalyses the first committed step in the biosynthesis of bacteriochlorophylls c, d, and e, the removal of the C-132-methylcarboxyl group from chlorophyllide a. The reaction is very similar to the conversion of pheophorbide a to pyropheophorbide a during chlorophyll a degradation, which is catalysed by EC 3.1.1.82, pheophorbidase.
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SYSTEMATIC NAME
IUBMB Comments
chlorophyllide-a hydrolase
This enzyme, found in green sulfur bacteria (Chlorobiaceae) and green filamentous bacteria (Chloroflexaceae), catalyses the first committed step in the biosynthesis of bacteriochlorophylls c, d, and e, the removal of the C-132-methylcarboxyl group from chlorophyllide a. The reaction is very similar to the conversion of pheophorbide a to pyropheophorbide a during chlorophyll a degradation, which is catalysed by EC 3.1.1.82, pheophorbidase.
BciC demethoxycarbonylase removes the C13(2)-methoxycarbonyl group to facilitate the self-aggregation of BChl c. The substrate specificity of BciC is measurably affected by structural changes on the A/B rings including the bacteriochlorin pi-systems. Moreover, BciC shows its activity on a Zn-chelated chlorophyll derivative. On the contrary, BciC recognizes structural modifications on the D/E rings, including porphyrin pigments, which resulted in the significant decrease in the enzymatic activity
a gene CT1077 deletion mutant is unable to synthesize bacteriochlorophyll BChl c but still synthesizes BChl a and Chl a. The deletion mutant accumulates large amounts of various (bacterio)pheophorbides, all of which still have C-132-methylcarboxyl groups. The mutant grows 10fold slower than the wild-type at the lowest light intensity applied but only grows 2fold slower at the highest light intensity
a gene CT1077 deletion mutant is unable to synthesize bacteriochlorophyll BChl c but still synthesizes BChl a and Chl a. The deletion mutant accumulates large amounts of various (bacterio)pheophorbides, all of which still have C-132-methylcarboxyl groups. The mutant grows 10fold slower than the wild-type at the lowest light intensity applied but only grows 2fold slower at the highest light intensity
the utilization of BciC provides mild conditions (45°C, 10 min) that may be useful for the in vitro preparation of various chemically (un)stable chlorophyllous pigments