Localized unfolding at the junction of three ferritin subunits. A mechanism for iron release?
Takagi, H., Shi, D., Ha, Y., Allewell, N.M., Theil, E.C.(1998) J Biol Chem 273: 18685-18688
- PubMed: 9668036
- DOI: https://doi.org/10.1074/jbc.273.30.18685
- Primary Citation of Related Structures:
1BG7 - PubMed Abstract:
How and where iron exits from ferritin for cellular use is unknown. Twenty-four protein subunits create a cavity in ferritin where iron is concentrated >10(11)-fold as a mineral. Proline substitution for conserved leucine 134 (L134P) allowed normal assembly but increased iron exit rates. X-ray crystallography of H-L134P ferritin revealed localized unfolding at the 3-fold axis, also iron entry sites, consistent with shared use sites for iron exit and entry. The junction of three ferritin subunits appears to be a dynamic aperture with a "shutter" that cytoplasmic factors might open or close to regulate iron release in vivo.
Organizational Affiliation:
Department of Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622, USA.