A novel hemerythrin DNase from the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC7120

► Alr3199 is functionally active as a DNase or Nickase depending on nature and concentration of cation present. ► Alr3199 has no domain homology with DNase/nicking endonuclease, but has two hemerythrin domains in the C-terminus. ► DNase/Nickase activity of Alr3199 resides in the N-terminal non-hemer...

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Veröffentlicht in:Archives of biochemistry and biophysics 2011-01, Vol.505 (2), p.171-177
Hauptverfasser: Padmaja, N., Rajaram, Hema, Apte, Shree Kumar
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Sprache:eng
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Zusammenfassung:► Alr3199 is functionally active as a DNase or Nickase depending on nature and concentration of cation present. ► Alr3199 has no domain homology with DNase/nicking endonuclease, but has two hemerythrin domains in the C-terminus. ► DNase/Nickase activity of Alr3199 resides in the N-terminal non-hemerythrin region and is modulated by Fe2+ bound to the C-terminal hemerythrin region. ► Alr3199 is the only hemerythrin protein known to have a DNase activity. 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.
ISSN:0003-9861
1096-0384
DOI:10.1016/j.abb.2010.10.007