1z6o
From Proteopedia
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Crystal Structure of Trichoplusia ni secreted ferritin
Overview
Ferritins are iron storage proteins made of 24 subunits forming a hollow, spherical shell. Vertebrate ferritins contain varying ratios of heavy (H), and light (L) chains; however, known ferritin structures include only one, type of chain and have octahedral symmetry. Here, we report the 1.9A, structure of a secreted insect ferritin from Trichoplusia ni, which, reveals equal numbers of H and L chains arranged with tetrahedral, symmetry. The H/L-chain interface includes complementary features, responsible for ordered assembly of the subunits. The H chain contains a, ferroxidase active site resembling that of vertebrate H chains with an, endogenous, bound iron atom. The L chain lacks the residues that form a, putative iron core nucleation site in vertebrate L chains. Instead, a, possible nucleation site is observed at the L chain 3-fold pore. The, structure also reveals inter- and intrasubunit disulfide bonds, mostly in, the extended N-terminal regions unique to insect ferritins. The, symmetrical arrangement of H and L chains and the disulfide crosslinks, reflect adaptations of insect ferritin to its role as a secreted protein.
About this Structure
1Z6O is a Protein complex structure of sequences from Trichoplusia ni with FE and CA as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of a secreted insect ferritin reveals a symmetrical arrangement of heavy and light chains., Hamburger AE, West AP Jr, Hamburger ZA, Hamburger P, Bjorkman PJ, J Mol Biol. 2005 Jun 10;349(3):558-69. Epub 2005 Apr 12. PMID:15896348
Page seeded by OCA on Sun Nov 25 04:45:44 2007
