caa a22 4500 605507007 CHVBK 20210128100630.0 cr unu---uuuuu 210128e20150901xx s 000 0 eng 10.1007/s00775-015-1279-x doi (NATIONALLICENCE)springer-10.1007/s00775-015-1279-x Fe2+ substrate transport through ferritin protein cage ion channels influences enzyme activity and biomineralization [Elektronische Daten] [Rabindra Behera, Rodrigo Torres, Takehiko Tosha, Justin Bradley, Celia Goulding, Elizabeth Theil] Ferritins, complex protein nanocages, form internal iron-oxy minerals (Fe2O3·H2O), by moving cytoplasmic Fe2+ through intracage ion channels to cage-embedded enzyme (2Fe2+/O2 oxidoreductase) sites where ferritin biomineralization is initiated. The products of ferritin enzyme activity are diferric oxy complexes that are mineral precursors. Conserved, carboxylate amino acid side chains of D127 from each of three cage subunits project into ferritin ion channels near the interior ion channel exits and, thus, could direct Fe2+ movement to the internal enzyme sites. Ferritin D127E was designed and analyzed to probe properties of ion channel size and carboxylate crowding near the internal ion channel opening. Glu side chains are chemically equivalent to, but longer by one -CH2 than Asp, side chains. Ferritin D127E assembled into normal protein cages, but diferric peroxo formation (enzyme activity) was not observed, when measured at 650nm (DFP λ max). The caged biomineral formation, measured at 350nm in the middle of the broad, nonspecific Fe3+-O absorption band, was slower. Structural differences (protein X-ray crystallography), between ion channels in wild type and ferritin D127E, which correlate with the inhibition of ferritin D127E enzyme activity include: (1) narrower interior ion channel openings/pores; (2) increased numbers of ion channel protein-metal binding sites, and (3) a change in ion channel electrostatics due to carboxylate crowding. The contributions of ion channel size and structure to ferritin activity reflect metal ion transport in ion channels are precisely regulated both in ferritin protein nanocages and membranes of living cells. SBIC, 2015 Ferritin nationallicence Iron oxidation nationallicence Ion channels nationallicence Crystal structure nationallicence Electrostatics nationallicence Di-iron center nationallicence Diferric peroxo nationallicence Caged iron-oxy biomineral nationallicence Oxidoreductase enzyme reactivity nationallicence DFP : Diferric peroxo nationallicence WT : Wild type nationallicence di-Fe2+/O2 center : Oxidoreductase or ferroxidase center (Fox Center) nationallicence Behera Rabindra Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut Torres Rodrigo Department of Molecular Biology and Biochemistry, University of California-Irvine, 92697, Irvine, CA, USA aut Tosha Takehiko Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut Bradley Justin Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut Goulding Celia Department of Molecular Biology and Biochemistry, University of California-Irvine, 92697, Irvine, CA, USA aut Theil Elizabeth Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/6(2015-09-01), 957-969 0949-8257 20:6<957 2015 20 775 https://doi.org/10.1007/s00775-015-1279-x text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00775-015-1279-x text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Behera Rabindra Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut NATIONALLICENCE 700 1- Torres Rodrigo Department of Molecular Biology and Biochemistry, University of California-Irvine, 92697, Irvine, CA, USA aut NATIONALLICENCE 700 1- Tosha Takehiko Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut NATIONALLICENCE 700 1- Bradley Justin Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut NATIONALLICENCE 700 1- Goulding Celia Department of Molecular Biology and Biochemistry, University of California-Irvine, 92697, Irvine, CA, USA aut NATIONALLICENCE 700 1- Theil Elizabeth Children's Hospital Oakland Research Institute (CHORI), 5700 Martin Luther King Jr. Way, 94609, Oakland, CA, USA aut NATIONALLICENCE 773 0- JBIC Journal of Biological Inorganic Chemistry Springer Berlin Heidelberg 20/6(2015-09-01), 957-969 0949-8257 20:6<957 2015 20 775