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

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• 作者：N. Padmaja^a ; Hema Rajaram ; ^a ; ^{hemaraj@barc.gov.in} ; Shree Kumar Apte^a
• 关键词：Anabaena PCC7120 ; Alr3199 ; Hemerythrin ; DNase ; Nickase ; Cation-dependence
• 刊名：Archives of Biochemistry and Biophysics
• 出版年：2011
• 出版时间：15 January 2011
• 年：2011
• 卷：505
• 期：2
• 页码：171-177
• 全文大小：858 K

文摘

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.