María Teresa Bes

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Promoter regions of the mcy operon from Microcystis aeruginosa PCC7806, which is responsible for microcystin synthesis in this organism, exhibit sequences that are similar to the sequences recognized by Fur (ferric uptake regulator). This DNA-binding protein is a sensor of iron availability and oxidative stress. In the presence of Fe(2+), a dimer of Fur(More)
The Fur (ferric uptake regulator) protein is a global regulator in most prokaryotes that controls a large number of genes. Fur is a classical repressor that uses ferrous iron as co-repressor and binds to specific DNA sequences (iron boxes) as a dimer. Three different genes coding for Fur homologues have been identified in Anabaena sp. PCC 7120. FurA(More)
Ferric uptake regulation (Fur) proteins are prokaryotic transcriptional regulators that integrate iron metabolism with several environmental stress responses. The regulatory network that governs Fur proteins is rather complex. Control at several stages from gene transcription to post-translational binding of different ligands has been reported in Fur from(More)
Microcystins are toxins produced by cyanobacteria that entail serious health and environmental problems. They are cyclic heptapeptides synthesized via a mixed polyketide synthase/non-ribosomal peptide synthetase system called microcystin synthetase. Environmental and nutritional factors that trigger microcystin synthesis are still debated and this work(More)
Ferric uptake regulator (Fur) proteins are widely recognized as repressors that in many prokaryotes regulate a large number of genes involved in iron homeostasis and oxidative stress response. In our study, we were able to identify the complete sequence of the fur gene from Microcystis aeruginosa using inverse-polymerase chain reaction. DNA sequence(More)
DNA sequence analysis of the Anabaena sp. PCC7120 genome confirmed the presence of three open reading frames (all1691, all2473 and alr0957) containing the histidine-rich region characteristic of the Fur family. The genes coding for the three Fur proteins were cloned and overexpressed in Escherichia coli. The overexpression products, called FurA, FurB and(More)
Fur (ferric uptake regulator) protein is a DNA-binding protein which regulates iron-responsive genes. Recombinant Fur from the nitrogen-fixing cyanobacterium Anabaena PCC 7119 has been purified and characterized, and polyclonal antibodies obtained. The experimental data show that Fur from Anabaena dimerizes in solution with the involvement of disulphide(More)
A gene coding for a Fur (ferric uptake regulation) protein from the cyanobacterium Anabaena PCC 7119 has been cloned and overexpressed in Escherichia coli. DNA sequence analysis confirmed the presence of a 151-amino-acid open reading frame that showed homology with the Fur proteins reported for the unicellular cyanobacteria Synechococcus 7942 and(More)
In this study, quantitative real time RT-PCR has been used to monitor changes in the levels of transcripts encoding mcyD in Microcystis aeruginosa PCC7806 under oxidative agents and different conditions of light intensity. Microcystin content has also been determined in the same stressed cell aliquots. Our results corroborate the fact that changes in light(More)
The binding affinity of NtcA towards promoter regions of the microcystin gene cluster from Microcystis aeruginosa PCC 7806 has been analyzed by band-shift assay (EMSA). The key nitrogen transcriptional regulator exhibits affinity for two fragments of the bidirectional mcyDA promoter, as well as for promoter regions of mcyE and mcyH. The presence of(More)