A novel hemerythrin DNase from the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC7120.
The open reading frame alr3199 of the nitrogen-fixing cyanobacterium, Anabaena sp. strain PCC7120 was cloned and overexpressed in Escherichia coli. Purified recombinant Alr3199 protein was found to be a functionally active deoxyribonuclease with novel features, such as (1) no homology to typical DNases (2) a Ca²(+)-dependent Nickase activity (3) presence of a di-hemerythrin domain, and (4) requirement of Fe²(+) conjugated to hemerythrin domains for optimal activity. Both the DNase and Nickase activities were found to be associated with the N-terminal non-hemerythrin region, but were modulated by Fe²(+) conjugated to the C-terminal hemerythrin region. This is the first report of a hemerythrin protein with DNase activity, tentatively designated as 'HE-DNase', and with a possible role in stress-induced DNA damage/repair in Anabaena.
Bhabha Atomic Research Centre, Trombay, Mumbai, India.
N
N
Padmaja
Hema
H
Rajaram
Shree Kumar
SK
Apte
D000595:Amino Acid Sequence; D017033:Anabaena / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D003001:Cloning, Molecular; D019295:Computational Biology; D003851:Deoxyribonucleases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006422:Hemerythrin / Q000378:metabolism*; D007501:Iron / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation; D017434:Protein Structure, Tertiary
D006422:Hemerythrin; D007501:Iron; D003851:Deoxyribonucleases