Do you know that see water contains heaps of Uranium (in form of UO2++ ion) with average concentration 13.7nM. Well, it looks not impressive but water in the ocean in total have 100o times more of uranium that our earth crust. Problem is that no one came up with an idea how efficiently extract this precious metal out of water. Also, remember that presence of a similar type metals such as Vanadium, Copper etc which are presented in a water at even higher concentration will be outcompeting Uranium. And just to make task even more daunting, carbonate complexate with uranyl ion what leaves only 10(-17) Mollar of free ion. Thus someone need to design a molecule with at least femtomolar affinity 10(-15) in order to effectively extract Uranyl at this negligibly low free concentration.
Group of Professors Luhua Lai (Peking University) and Chuan He (Chikago University) engineered a protein with fM affinity for Uranyl ion! They just have published in recent Nature Chemistry issue. The collaborative workflow they have presented in the paper is tremendous! Briefly, they computed around 13000 of PDB known scaffolds for mutants that possibly can bind Uranyl which 'ccordination' geometry is very well known. They came up with 5000 hits, after couple of rounds of refining the library they were able to pick around ten with only four proteins amenable for expression. The best candidate has an affinity 37nM wich is far from perfect, but good luck and some of computation tricks led them to find a mutant with 1000-higher affinity (fM!). They were able to extract up to 95% of Uranyl from synthetic see water leaving just 3 ppb (!) of Uranyl in the filtrate. Now they are thinking of cheap device that would be able to replenish itself with protein Uranyl-binder. The most simple would be to use bacterias who can express this protein on the surface. So just by simply growing these bacterias now one can extract uranium out of see water. Although a whole idea is very smart and environmentally friendly (simple filtration of ocean water), use of bacterias will require stringent stages of water purification after it's been in contact with biomass given the huge masses of water that will be passing though these 'filters'.
Group of Professors Luhua Lai (Peking University) and Chuan He (Chikago University) engineered a protein with fM affinity for Uranyl ion! They just have published in recent Nature Chemistry issue. The collaborative workflow they have presented in the paper is tremendous! Briefly, they computed around 13000 of PDB known scaffolds for mutants that possibly can bind Uranyl which 'ccordination' geometry is very well known. They came up with 5000 hits, after couple of rounds of refining the library they were able to pick around ten with only four proteins amenable for expression. The best candidate has an affinity 37nM wich is far from perfect, but good luck and some of computation tricks led them to find a mutant with 1000-higher affinity (fM!). They were able to extract up to 95% of Uranyl from synthetic see water leaving just 3 ppb (!) of Uranyl in the filtrate. Now they are thinking of cheap device that would be able to replenish itself with protein Uranyl-binder. The most simple would be to use bacterias who can express this protein on the surface. So just by simply growing these bacterias now one can extract uranium out of see water. Although a whole idea is very smart and environmentally friendly (simple filtration of ocean water), use of bacterias will require stringent stages of water purification after it's been in contact with biomass given the huge masses of water that will be passing though these 'filters'.
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