Authors: SHEN TIAN, SILI CHEN, FENGJIAO GONG
Abstract: The genes coding for methyltransferase during the maturation of phycobilisomes in Synechococcus sp. strain PCC 7002 and Synechocystis sp. strain PCC 6803 were indentified and named CpcM. Using bioinformatics methods, it was found that a probable methyltransferase gene denoted all0012, because of its highly similarity, is likely to be the molecule that edits and modifies the \beta-subunit in Anabaena sp. strain PCC 7120. The present study was intended to analyze the probable functions of gene all0012. After bioinformatic analyses, we constructed an appropriate heterologous all0012 expression carrier and the characteristics of expression were evaluated by SDS-PAGE. Afterwards, a deletion mutant was characterized via a shuttle vector by means of triparental transformation. Intact phycobilisomes were separately isolated from null mutant and wild-type strains and their absorption spectra were compared. To further analyze possible functions of all0012, null alleles of cyanobacteria were cultured in the same specific conditions as the wild type under various intensities of light. The absorbance properties of the null mutant were very similar to those of the wild-type. Meanwhile, a dramatic photosensitization difference was observed under high-level illumination, which is similar to the phenotype of methylation-deficient strains observed in previous research. This study suggests that the gene may play an important role in the methylation of the \beta-subunit of phycobiliprotein.
Keywords: Cyanobacteria, methyltransferase, triparental conjugation
Full Text: PDF