A Novel DNA Modification by Sulfur: DndA Is a NifS-like Cysteine Desulfurase Capable of Assembling DndC as an Iron-Sulfur Cluster Protein in Streptomyces lividans
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- 作者：Delin You ; Lianrong Wang ; Fen Yao ; Xiufen Zhou ; Zixin Deng
- 刊名：Biochemistry
- 出版年：2007
- 出版时间：May 22, 2007
- 年：2007
- 卷：46
- 期：20
- 页码：6126 - 6133
- 全文大小：113K
- 年卷期：v.46,no.20(May 22, 2007)
- ISSN：1520-4995
文摘
A novel DNA modification system by sulfur (S) in Streptomyces lividans 66 was reported tobe encoded by a cluster of five genes designated dndA-E [Zhou, X., He, X., Liang, J., Li, A., Xu, T.,Kieser, T., Helmann, J. D., and Deng, Z. (2005) Mol. Microbiol. 57, 1428-1438]. The dndA gene wascloned and the protein product expressed in Escherichia coli, purified to homogeneity, and characterizedas a homodimeric protein of ca. 91 kDa. Purified DndA has a yellow color and UV-visible spectracharacteristic of a pyridoxal phosphate-containing enzyme and was proven to be a cysteine desulfuraseable to catalyze removal of elemental S atoms from L-cysteine to produce L-alanine with substrate specificitysimilar to that of E. coli IscS. DndC was also purified to homogeneity and found to contain a 4Fe-4Scluster by spectral analysis and have obvious ATP pyrophosphatase activity. DndA could catalyze iron-sulfur cluster assembly by activation of apo-Fe DndC protein prepared by removal of its iron-sulfurcluster using 
,'-dipyridyl. A mutated DndA, with serine substituted for cysteine at position 327, whichwas confirmed to have lost its corresponding cysteine desulfurase activity, also lost its ability to reactivatethe apo-Fe DndC. The likely involvement of an interaction between DndA and DndC in the biochemicalpathway for the unusual site-specific DNA modification in S. lividans 66 is discussed.
,'-dipyridyl. A mutated DndA, with serine substituted for cysteine at position 327, whichwas confirmed to have lost its corresponding cysteine desulfurase activity, also lost its ability to reactivatethe apo-Fe DndC. The likely involvement of an interaction between DndA and DndC in the biochemicalpathway for the unusual site-specific DNA modification in S. lividans 66 is discussed.