Gupta, Surbhi ; Chatterji, Dipankar (2003) Bimodal protection of DNA by Mycobacterium smegmatis DNA-binding protein from stationary phase cells Journal of Biological Chemistry, 278 . pp. 5235-5241. ISSN 0021-9258
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Official URL: http://www.jbc.org/content/278/7/5235.abstract
Related URL: http://dx.doi.org/10.1074/jbc.M208825200
Abstract
Some members of the DNA-binding protein from stationary phase cells (Dps) family of proteins have been shown to play an important role in protecting microorganisms from oxidative or nutritional stress. Dps homologs have been identified in various bacteria such as Escherichia coli, Bacillus subtilis, and Listeria innocua. Recently we have reported the presence of a Dps homolog, Ms-Dps, in Mycobacterium smegmatis. Ms-Dps was found to have a nonspecific DNA binding ability. Here we have detected two stable oligomeric forms of Ms-Dpsin vitro, a trimeric and a dodecameric form. Interestingly, the conversion of Dps from a trimeric to a dodecameric form takes place upon incubation at 37° C for 12 h. These two oligomeric forms differ in their DNA binding properties. The dodecameric form is capable of DNA binding and forming large crystalline arrays with DNA, whereas the trimeric form cannot do so. However, even in the absence of DNA binding, the trimeric form has the capacity to protect the DNA against Fenton's-mediated damage. The protection is afforded by the ferroxidase activity of the trimer. However, the trimeric form cannot protect DNA from DNaseI attack, for which a direct physical shielding of DNA by the dodecamer is required. Thus we suggest that Ms-Dps provides a bimodal protection of DNA by its two different oligomeric forms.
Item Type: | Article |
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Source: | Copyright of this article belongs to American Society for Biochemistry and Molecular Biology. |
ID Code: | 6292 |
Deposited On: | 20 Oct 2010 11:16 |
Last Modified: | 16 May 2016 16:38 |
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