2V2I

Wild type recombinant horse spleen apoferritin cocrystallized with haemin in acidic conditions

Summary for 2V2I

• Entry DOI: 10.2210/pdb2v2i/pdb
• Related: 1AEW 1DAT 1GWG 1HRS 1IER 1IES 1XZ1 1XZ3 2V2J 2V2L 2V2M 2V2N 2V2O 2V2P 2V2R 2V2S 2W0O
• Descriptor: FERRITIN LIGHT CHAIN, CADMIUM ION, GLYCEROL, ... (5 entities in total)
• Functional Keywords: metal transport, iron, haemin, apoferritin, iron storage, metal-binding
• Biological source: EQUUS CABALLUS (HORSE)
• Total number of polymer chains: 1
• Total formula weight: 21075.03

Authors

De Val, N.,Declercq, J.P. (deposition date: 2007-06-06, release date: 2008-06-24, Last modification date: 2023-12-13)

Primary citation

De Val, N.,Declercq, J.P.,Lim, C.K.,Crichton, R.R.
Structural Analysis of Haemin Demetallation by L-Chain Apoferritins
J.Inorg.Biochem., 112:77-, 2012

PubMed Abstract: There are extensive structural similarities between eukaryotic and prokaryotic ferritins. However, there is one essential difference between these two types of ferritins: bacterioferritins contain haem whereas eukaryotic ferritins are considered to be non-haem proteins. In vitro experiments had shown that horse spleen apoferritin or recombinant horse L chain apoferritins, when co-crystallised with haemin, undergoes demetallation of the porphyrin. In the present study a cofactor has been isolated directly from horse spleen apoferritin and from crystals of the mutant horse L chain apoferritin (E53Q, E56Q, E57Q, E60Q and R59M) which had been co-crystallised with haemin. In both cases the HPLC/ESI-MS results confirm that the cofactor is a N-ethylprotoporphyrin IX. Crystal structures of wild type L chain horse apoferritin and its three mutants co-crystallised with haemin have been determined to high resolution and in all cases a metal-free molecule derived from haemin was found in the hydrophobic pocket, close to the two-fold axis. The X-ray structure of the E53Q, E56Q, E57Q, E60Q+R59M recombinant horse L-chain apoferritin has been obtained at a higher resolution (1.16Å) than previously reported for any mammalian apoferritins. Similar evidence for a metal-free molecule derived from haemin was found in the electron density map of horse spleen apoferritin (at a resolution of 1.5Å). The out-of-plane distortion of the observed porphyrin is clearly compatible with an N-alkyl porphyrin. We conclude that L-chain ferritins are capable of binding and demetallating haemin, generating in the process N-ethylprotoporphyrin IX both in vivo and in vitro.

PubMed: 22561545
DOI: 10.1016/J.JINORGBIO.2012.02.031

Experimental method

X-RAY DIFFRACTION (2 Å)