engleski

The function of a rhodanese under sulfur limitation conditions in cyanobacterium Synechocystis sp. PCC 6803

Rhodaneses are widespread enzymes that catalyze the transfer of a sulfane sulfur atom from thiosulfate to cyanide in vitro. Their biological role is still largely debated, since the identification of their biological substrates has proven to be elusive. In the genome of cyanobacteria Synechocystis sp. PCC 6803 gene slr0192 that encodes putative 12 kDa protein has been identified. Sequence analysis showed similarity to the rhodanese-like domains from other organisms. The subject of this work has been the characterization of a potential rhodanese and the determination of its function in vivo in the cyanobacterium Synechocystis sp. PCC 6803. For that purpose, the mutant strain with a disrupted gene slr0192 has been constructed by method of an insertional gene inactivation. Southern blot and polymerase chain reaction analysis showed that the mutant had completely segregated. The aim was to define the influence of the matching protein on the physiology of an organism by comparing mutant and wild type strains. Analysis of photoautotrophic growth curves, electron microscopy of the cells, apsorption spectra and chlorophyll autofluorescence did not show any significant difference between wild type strain and Δ slr0192 mutant under normal conditions. Rhodanese activities were obtained for crude enzyme extract of cyanobacterial cells. Potential role has been also examined under sulfur deprivation conditions. A difference in phenotype was observed that manifested in longer viability of mutant cells. This report is a base for further studies of slr0192 exact role under the conditions of sulfur deprivation in cyanobacteria Synechocystis sp. PCC 6803.

rhodanese; insertional inactivation; sulfur metabolism; electron microscopy

ISBN 953-6241-06-4