Transcriptional regulation and structural modeling of the FutC subunit of an ABC-type iron transporter in Synechocystis sp. strain PCC 6803

Abstract

The futC gene encodes a subunit of an ATP-binding cassette (ABC)-type iron transporter in Synechocystis sp. strain PCC 6803. In the present study, we have focused on the environmental regulation of futC transcription in the model organism Synechocystis sp. strain PCC 6803 and, moreover, studied the transcriptional regulation of the other transporter subunits, futA1, futA2 and futB. The steady-state amounts of the futA1, futA2, futB and futC transcripts were regulated under several conditions studied including darkness, temperature, alternative nitrogen source, salt and osmotic stresses and iron deficiency. Transcription of all subunits of the FutABC-iron transporter seems to be under similar regulation, which, according to our results, may also apply to genes encoding subunits of other transporters in Synechocystis. The sequence alignment, including sequences from six different organisms, revealed the conserved nature of FutC. Based on the sequence alignment and the structural model of FutC, the monomer consists of a nucleotide-binding domain (NBD) and a regulatory domain. The NBD is well conserved indicating completely functional ATP binding.

On the trail of iron uptake in ancestral Cyanobacteria on early Earth

“…PCC 6803, namely FutA, FutB and FutC (Brandt et al, 2009;Katoh et al, 2001), FTR1 (Katoh et al, 2000), FeoB (Katoh et al, 2001;Kranzler et al, 2014), ExbB/D TonB (Jiang et al, 2015;Qiu et al, 2018) and the related E. coli iron transporters (Altschul, 1991(Altschul, , 1993Zhang et al, 2000) and Shewanella oneidensis FicI transporter (Bennett et al, 2018). The identification of hits of FutABC, cFTR1, FurA, FeoABC, ZIP and NRAMPs found in Pseudanabaena sp.…”

“…Uncomplexed iron can enter the periplasmic space via TonB‐dependent transporters (TBDTs) shown as the orange rectangle (Jiang et al, 2015; Qiu et al, 2018) or outer membrane porins, indicated by a gray square (Qiu et al, 2021). Cyanobacteria make use of specific transporters to facilitate inorganic iron uptake into the cytoplasm: The FutABC system facilitates Fe(III) uptake into the cell (Brandt et al, 2009; Katoh et al, 2001), while FeoB is the primary transporter for Fe(II) (Katoh et al, 2001; Kranzler et al, 2014). The zinc‐iron permease (ZIP) (Morrissey & Bowler, 2012), the natural resistance‐associated macrophage protein (NRAMP) homologue (Nevo & Nelson, 2006) and FicI (Bennett et al, 2018) are thought to take up Fe(II) and other divalent cationic metals, indicated in red text.…”

Novel adsorptive materials by adenosine 5ʹ‐triphosphate imprinted‐polymer over the surface of polystyrene nanospheres for selective separation of adenosine 5ʹ‐triphosphate biomarker from urine

“…The MIP prepared against methyl adenosine template, using MAA functional monomer and EGDMA crosslinker demonstrated a low adsorption capacity (20 µmol/g) for SPE application from urine . Since ATP is composed of adenine, ribofuranose, and triphosphate concertedly contributing 13 binding sites for its recognition and its structure binds specific natural receptors having amino acids with noncovalent interaction . The N i ‐AAm is suitable for binding with nucleobase amine moieties and phosphates groups and MAA is suitable for the binding sites of ribose hydroxyls of AMP like to boronic acid and also the DMAEMA chosen in this study to bind with phosphate groups .…”

Lack of Fe(II) transporters in basal Cyanobacteria complicates iron uptake in ferruginous Archean oceans

“…To do this, 125 genomes (Supplementary data file 1) were screened with protein sequence similarity searches (March 2020 & May 2021) using BLASTP (Altschul 1991;Altschul 1993;Zhang et al, 2000) with e-value cut-offs less than 0.001 for the following genes linked to iron transporters identified in Synechocystis sp. PCC6803, namely FutA, FutB and FutC (Brandt et al, 2009;Katoh et al, 2001), FTR1 (Katoh et al, 2000), FeoB (Katoh et al, 2001;Kranzler et al, 2014), ExbB/D TonB (Qiu et al, 2018;Jiang et al, 2015) and the related E. coli iron transporters (Altschul, 1991;Altschul, 1993;Zhang et al, 2000). The identification of hits found in Pseudanabaena sp.…”

“…1 Inorganic iron uptake in Cyanobacteria. Cyanobacteria make use of specific transporters to facilitate inorganic iron uptake: The FutABC system facilitates Fe(III) uptake into the cell (Katoh et al, 2001;Brandt et al, 2009), while FeoB is the primary transporter for Fe(II) (Katoh et al, 2001;Kranzler et al, 2014). The zinc-iron permease (ZIP) (Morrissey and Bowler 2012) and the natural resistance associated macrophage protein (NRAMP) 7 homologue (Nevo and Nelson 2006) are thought to take up Fe(II) and other divalent cationic metals.…”