5h46
Mycobacterium smegmatis Dps1 mutant - F47E
Structural highlights
FunctionDPS_MYCS2 Protects DNA from oxidative damage by sequestering intracellular Fe(2+) ion and storing it in the form of Fe(3+) oxyhydroxide mineral. One hydrogen peroxide oxidizes two Fe(2+) ions, which prevents hydroxyl radical production by the Fenton reaction (By similarity). It protects DNA from hydroxyl radical-mediated cleavage. Binds DNA with no apparent sequence specificity without self-aggregation nor promotion of DNA condensation. Is unable to protect DNA from DNase-mediated cleavage (By similarity). Publication Abstract from PubMedProteins of the ferritin family are ubiquitous in living organisms. With their spherical cage-like structures they are the iron storehouses in cells. Subfamilies of ferritins include 24-meric ferritins and bacterioferritins (maxiferritins), and 12-meric Dps (miniferritins). Dps safeguards DNA by direct binding, affording physical protection and safeguards from free radical-mediated damage by sequestering iron in its core. The maxiferritins can oxidize and store iron but cannot bind DNA. Here we show that a mutation at a critical interface in Dps alters its assembly from the canonical 12-mer to a ferritin-like 24-mer under crystallization. This structural switch was attributed to the conformational alteration of a highly conserved helical loop and rearrangement of the C-terminus. Our results demonstrate a novel concept of mutational switch between related protein subfamilies and corroborate the popular model for evolution by which subtle substitutions in an amino acid sequence lead to diversification among proteins. A Mutation Directs the Structural Switch of DNA Binding Proteins under Starvation to a Ferritin-like Protein Cage.,Williams SM, Chandran AV, Prakash S, Vijayan M, Chatterji D Structure. 2017 Aug 2. pii: S0969-2126(17)30221-6. doi:, 10.1016/j.str.2017.07.006. PMID:28823472[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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