Identification and biochemical properties of Dps (starvation-induced DNA binding protein) from cyanobacterium Anabaena sp. PCC 7120.
DNA-binding Proteins from Starved cells (Dps) are anti-stress iron proteins preserving bacteria from oxidative damage. Based on sequence alignment, a 564-bp open reading frame (all1173) encoding product in Anabaena sp. PCC 7120 shared high similarity with Dps family proteins. RT-PCR showed all1173 is active at transcriptional level in Anabaena sp. PCC 7120 cells. We accordingly cloned the all1173 into prokaryotic expression system, purified the corresponding recombinant protein (Dps1173) and characterized its properties in vitro. According to CD spectrum and non-denaturing electrophoresis assays, recombinant Dps1173 was alpha helix riched, and was likely to form dodecametric oligomer under native conditions. Fluorescence titration experiment revealed two major iron binding sites within Dps1173 monomer, indicating its potential ferroxidase activity. Although phenomena of direct DNA binding was not observed in Electrophoretic mobility shift assay, Dps1173 could also protect DNA from H2O2 stress for its iron scavenging capacity. This is the first description of Dps from heterocystous cyanobacterium Anabaena sp. PCC 7120.
Wei
Xiong
X
Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing, PR China.
Mingjia
He
H
Xiufeng
Li
L
Yang
Gao
G
Qingyu
Wu
W
D000595:Amino Acid Sequence; D017033:Anabaena / Q000737:chemistry* / Q000201:enzymology / Q000502:physiology*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D001665:Binding Sites; D002570:Ceruloplasmin / Q000737:chemistry / Q000502:physiology; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism / Q000502:physiology*; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D008969:Molecular Sequence Data
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; C083911:DPS protein, Bacteria; D033862:Iron-Binding Proteins; D007501:Iron; D002570:Ceruloplasmin