2clb: Difference between revisions
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==Overview== | ==Overview== | ||
The superfamily of ferritin-like proteins has recently expanded to include, a phylogenetically distinct class of proteins termed DPS-like (DPSL), proteins. Despite their distinct genetic signatures, members of this, subclass share considerable similarity to previously recognized DPS, proteins. Like DPS, these proteins are expressed in response to oxidative, stress, form dodecameric cage-like particles, preferentially utilize, H(2)O(2) in the controlled oxidation of Fe(2+), and possess a short, N-terminal extension implicated in stabilizing cellular DNA. Given these, extensive similarities, the functional properties responsible for the, preservation of the DPSL signature in the genomes of diverse prokaryotes, have been unclear. Here, we describe the crystal structure of a DPSL, protein ... | The superfamily of ferritin-like proteins has recently expanded to include, a phylogenetically distinct class of proteins termed DPS-like (DPSL), proteins. Despite their distinct genetic signatures, members of this, subclass share considerable similarity to previously recognized DPS, proteins. Like DPS, these proteins are expressed in response to oxidative, stress, form dodecameric cage-like particles, preferentially utilize, H(2)O(2) in the controlled oxidation of Fe(2+), and possess a short, N-terminal extension implicated in stabilizing cellular DNA. Given these, extensive similarities, the functional properties responsible for the, preservation of the DPSL signature in the genomes of diverse prokaryotes, have been unclear. Here, we describe the crystal structure of a DPSL, protein from the thermoacidophilic archaeon Sulfolobus solfataricus., Although the overall fold of the polypeptide chain and the oligomeric, state of this protein are indistinguishable from those of authentic DPS, proteins, several important differences are observed. First, rather than a, ferroxidase site at the subunit interface, as is observed in all other DPS, proteins, the ferroxidase site in SsDPSL is buried within the four-helix, bundle, similar to bacterioferritin. Second, the structure reveals a, channel leading from the exterior surface of SsDPSL to the, bacterioferritin-like dimetal binding site, possibly allowing divalent, cations and/or H(2)O(2) to access the active site. Third, a pair of, cysteine residues unique to DPSL proteins is found adjacent to the dimetal, binding site juxtaposed between the exterior surface of the protein and, the active site channel. The cysteine residues in this thioferritin motif, may play a redox active role, possibly serving to recycle iron at the, ferroxidase center. | ||
==About this Structure== | ==About this Structure== | ||
2CLB is a | 2CLB is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Sulfolobus_solfataricus Sulfolobus solfataricus] with ZN and FE as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2CLB OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: oxidative stress]] | [[Category: oxidative stress]] | ||
''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 13:52:25 2007'' | ||
