Nídia Almeida

Research Areas

PhD Thesis: “Use of biological based nanocages for radiation protection and cellular detoxification" (2015-2019)

Advisers: Prof.ª Doutora Alice Pereira and Prof. Doutor Pedro Tavares

All#H%type proteins of the ferritin family are  ferroxidases capable of sequester, oxidize and mineralize ferrous ions. The ferritin family can be divided into two types of enzymes: i) the maxi%ferritins;  and  ii) mini%ferritins. Maxi%ferritins arZ large spherical cages capable of oxidizing ferrous iron at different  rates and  store it in a mineral core  form  (ca. 4500 irons per molecule).  These  enzymes  are  constituted  by  24  identical (for  example  in  bacterial ferritins) or different subunits (such as in mammalian  ferritins) and may contain additional cofactors for which a role is still under discussion (such as heme groups in bacterioferritins). To  achieve  Fe(II)  oxidation,  molecular  oxygen and/or  hydrogen  peroxide is  used  as  co% substrate,  and  oxidation  rate  is  dependent  of  the  presence  of ferroxidase sites,  generally binuclear  carboxylate  bridged  centers.  Mini%ferritins  are  smaller  spherical  cage  proteins mainly  constituted  by  12  identical subunits. While  capable  of  storing  near  500  atoms  per molecule,  these  enzymes  primary  task  is  to  sequester  ferrous  iron  while  using  hydrogen peroxide as co%substrate. These different sized hollow spheres can be used  to incorporate different  metal  ions  as  well  as  other  molecules.  Furthermore,  they  can  be  specifically altered  to  produce  chimeric molecules with additional  functionalities. In  this  PhD  plan we aim  to  produce  ferritin%based  functional  nanocages  capable  of  being  used  in  radiation protection, cancer cell targeting, drug delivery systems and biosensors.