Molecular cloning and expression analysis of a new bilin lyase: the cpcT gene encoding a bilin lyase responsible for attachment of phycocyanobilin to Cys-153 on the β-subunit of phycocyanin in
Arthrospira platensis FACHB314.
Gene 2014;
544:191-7. [PMID:
24768724 DOI:
10.1016/j.gene.2014.04.050]
[Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 04/21/2014] [Accepted: 04/22/2014] [Indexed: 11/18/2022]
Abstract
To study the assembly of phycocyanin β subunit, the gene cpcT was first cloned from Arthrospira platensis FACHB314. To explore the function of cpcT, the DNA of phycocyanin β subunit and cpcT were transformed into Escherichia coli BL21 with the plasmid pET-hox1-pcyA, which contained the genes hemeoxygenase 1 (Hox1) and ferredoxin oxidoreductase (PcyA) needed to produce phycocyanobilin. The transformed strains showed specific phycocyanin fluorescence, and the fluorescence intensity was stronger than the strains with only phycocyanin β subunit, indicating that CpcT can promote the assembly of phycocyanin to generate fluorescence. To study the possible binding sites of apo-phycocyanin and phycocyanobilin, the Cys-82 and Cys-153 of the β subunit were individually mutated, giving two kinds of mutants. The results show that Cys-153 maybe the active site for β subunit binding to phycocyanobilins, which is catalyzed by CpcT in A. platensis FACHB314.
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