The crystal structure of ferritin from Helicobacter pylori reveals unusual conformational changes for iron uptake.
The crystal structure of recombinant ferritin from Helicobacter pylori has been determined in its apo, low-iron-bound, intermediate, and high-iron-bound states. Similar to other members of the ferritin family, the bacterial ferritin assembles as a spherical protein shell of 24 subunits, each of which folds into a four-alpha-helix bundle. Significant conformational changes were observed at the BC loop and the entrance of the 4-fold symmetry channel in the intermediate and high-iron-bound states, whereas no change was found in the apo and low-iron-bound states. The imidazole rings of His149 at the channel entrance undergo conformational changes that bear resemblance to heme configuration and are directly coupled to axial translocation of Fe ions through the 4-fold channel. Our results provide the first structural evidence of the translocation of Fe ions through the 4-fold channel in prokaryotes and the transition from a protein-dominated process to a mineral-surface-dominated process during biomineralization.
Cho
Ki Joon
KJ
Department of Life Sciences and Biotechnology, Korea University, Seoul, Korea.
Shin
Hye Jeong
HJ
Lee
Ji-Hye
JH
Kim
Kyung-Jin
KJ
Park
Sarah S
SS
Lee
Youngmi
Y
Lee
Cheolju
C
Park
Sung Soo
SS
Kim
Kyung Hyun
KH
D000494:Allosteric Regulation; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018360:Crystallography, X-Ray; D005293:Ferritins / Q000737:chemistry* / Q000378:metabolism*; D016480:Helicobacter pylori / Q000737:chemistry*; D007501:Iron / Q000378:metabolism*; D008958:Models, Molecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary
D001426:Bacterial Proteins; C431650:pfr protein, Helicobacter pylori; D005293:Ferritins; D007501:Iron