Azo dyes have become a threat to public health because of its toxicity and carcinogenicity. Azoreductase enzyme plays a pivotal
role in the degradation of azodyes released by industrial effluents and other resources. The degradation pathway has to be studied
in detail for increasing the activity of azoreductase and for better degradation of azo dyes. But the data available on cyanobacterial
azoreductase enzyme and its degradation pathway are still very less. Therefore the present work explored the azoreductase
pathway of the cyanobacterium Nostoc sp. PCC7120 for better understanding of the degradation pathway and the other accessory
interacting proteins involved. The accessory interacting proteins of azoreductase from cyanobacterium Nostoc sp. PCC7120 were
obtained from STRING database. The proteins do not have a comprehensive three dimensional structure and are hypothetical. The
secondary structure and functional analysis indicated that the proteins are all soluble proteins, without disulphide bonds and have
alpha helices only. The structural prediction and docking study showed that alr2106, alr1063 and alr2326 have best docking result
which tally with the STRING database confidence score and thus these proteins could possibly enhance the azoreductase activity
and better dye degradation. These results will pave way for further increase in azoreductase activity and for better understanding
of the dye degradation pathway.
We present evidence, for the first time, of the occurrence of a transport system common for amino acid methionine, and methionine/glutamate analogues L-methionine-DL-sulfoximine (MSX) and phosphinothricin (PPT) in cyanobacterium Nostoc muscorum. Methionine, which is toxic to cyanobacterium, enhanced its nitrogenase activity at lower concentrations. The cyanobacterium showed a biphasic pattern of methionine uptake activity that was competitively inhibited by the amino acids alanine, isoleucine, leucine, phenylalanine, proline, valine, glutamine, and asparagine. The methionine/glutamate analogue-resistant N. muscorum strains (MSX-R and PPT-R strains) also showed methionine-resistant phenotype accompanied by a drastic decrease in 35S methionine uptake activity. Treatment of protein extracts from these mutant strains with MSX and PPT reduced biosynthetic glutamine synthetase (GS) activity only in vitro and not in vivo. This finding implicated that MSX- and PPT-R phenotypes may have arisen due to a defect in their MSX and PPT transport activity. The simultaneous decrease in methionine uptake activity and in vitro sensitivity toward MSX and PPT of GS protein in MSX- and PPT-R strains indicated that methionine, MSX, and PPT have a common transport system that is shared by other amino acids as well in N. muscorum. Such information can become useful for isolation of methionine-producing cyanobacterial strains.
Industrial dyes such as azodyes are potential environmental pollutants causing deleterious health hazards complications. These dyes are potentially degraded by azoreductase enzyme which is widely distributed in bacteria and also cyanobacteria. The azoreductase enzymes from cyanobacteria have not been explored in detail. Hence this enzyme from Nostoc sp. PCC 7120 has been addressed in detail in the present study considering to explore the physico-chemical properties, evolutionary relationships, functional sites and structural properties using various bioinformatics tools. Four conserved regions were obtained from the multiple sequence analysis. The multiple sequence alignment showed conserved regions at different stretches from 1-11, 40-57, 82-120 and 161-177 amino acid residues. These regions could be used for designing degenerate primers or probes for PCR-based amplification or hybridization-based detection of azoreductase sequences from different source organisms. Domain analysis and functional site prediction showed the presence of functional sites and domain such as flavodoxin like fold responsible for enzyme activity. 3D model was constructed and the best model was selected and validated. Superimposition of the final structure and the template showed variations in certain regions which might be involved in the accommodation of various dyes. Our results may be helpful for further investigations like docking studies as well as in vivo and in vitro conditions although these predictions still need to be studied.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.