1rfk | pdb_00001rfk
Crystal Structure of 2Fe2S Ferredoxin from Thermophilic Cyanobacterium Mastigocladus Laminosus
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Overview
Plant-type ferredoxins (Fds) carry a single [2Fe-2S] cluster and serve as, electron acceptors of photosystem I (PSI). The ferredoxin from the, thermophilic cyanobacterium Mastigocladus laminosus displays optimal, activity at 65 degrees C. In order to reveal the molecular factors that, confer thermostability, the crystal structure of M.laminosus Fd (mFd) was, determined to 1.25 A resolution and subsequently analyzed in comparison, with four similar plant-type mesophilic ferredoxins. The topologies of the, plant-type ferredoxins are similar, yet two structural determinants were, identified that may account for differences in thermostability, a salt, bridge network in the C-terminal region, and the flexible L1,2 loop that, increases hydrophobic accessible surface area. These conclusions were, verified by three mutations, i.e. substitution of L1,2 into a rigid, beta-turn ((Delta)L1,2) and two point mutations (E90S and E96S) that, disrupt the salt bridge network at the C-terminal region. All three, mutants have shown reduced electron transfer (ET) capabilities and, [2Fe-2S] stability at high temperatures in comparison to the wild-type, mFd. The results have also provided new insights into the involvement of, the L1,2 loop in the Fd interactions with its electron donor, the PSI, complex.
About this Structure
1RFK is a Single protein structure of sequence from Mastigocladus laminosus with FES as ligand. Full crystallographic information is available from OCA.
Reference
Structural basis for the thermostability of ferredoxin from the cyanobacterium Mastigocladus laminosus., Fish A, Danieli T, Ohad I, Nechushtai R, Livnah O, J Mol Biol. 2005 Jul 15;350(3):599-608. PMID:15961101
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