A novel recombinant chlorophyllase from cyanobacterium Cyanothece sp. ATCC 51142 for the production of bacteriochlorophyllide a

• Published in: Biotechnology and applied biochemistry Vol. 63; no. 3; p. 371
• Main Authors: Chou, Yi-Li, Lee, Ya-Lin, Yen, Chih-Chung, Chen, Long-Fang O, Lee, Li-Chiun, Shaw, Jei-Fu
• Format: Journal Article
• Language: English
• Published: United States 01.05.2016
• Subjects: Amino Acid Sequence; Bacteriochlorophyll A - biosynthesis; Carboxylic Ester Hydrolases - chemistry; Carboxylic Ester Hydrolases - genetics; Carboxylic Ester Hydrolases - metabolism; Cloning, Molecular; Cyanothece - enzymology; Cyanothece - genetics; Kinetics; Recombinant Proteins - chemistry; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Substrate Specificity; Cyanothece sp. ATCC 51142; chlorophyllase; kinetic analyses; biochemical analyses; biocatalyst; bacteriochlorin a
• ISSN: 1470-8744
• DOI: 10.1002/bab.1380

Bacteriopheophorbide a (BPheid a) is used as a precursor for bacteriochlorin a (BCA), which can be used for photodynamic therapy in both in vitro and in vivo biochemical applications. This study successfully isolated and expressed a photosynthetic bacterium (Cyanothece sp. ATCC 51142) chlorophyllase called CyanoCLH, which can be used as a biocatalyst for the production of a BCA precursor by degrading bacteriochlorophyll a (BChl a). Substrate specificity and enzyme kinetic analyses were performed and the results verified that the recombinant CyanoCLH preferred hydrolyzing BChl a to produce bacteriochlorophyllide a (BChlide a), which can be converted to BPheid a by removing magnesium ion. The recombinant CyanoCLH was cloned and expressed in Escherichia coli BL-21 (DE3), and its molecular weight was 54.7 kDa. The deduced amino acid sequence of the recombinant CyanoCLH comprised a unique lipase-motif GHSLG, which differs from the GHSRG sequence of other plants and lacks a histidine of the typical and conserved catalytic triad Ser-Asp-His. The recombinant CyanoCLH was subjected to biochemical analyses, and the results indicated that its optimal pH and temperature were 7.0 and 60 °C, respectively.