A protein engineered to bind uranyl selectively and with femtomolar affinity

Abstract

Uranyl (UO2(2+)), the predominant aerobic form of uranium, is present in the ocean at a concentration of ~3.2 parts per 10(9) (13.7 nM); however, the successful enrichment of uranyl from this vast resource has been limited by the high concentrations of metal ions of similar size and charge, which makes it difficult to design a binding motif that is selective for uranyl. Here we report the design and rational development of a uranyl-binding protein using a computational screening process in the initial search for potential uranyl-binding sites. The engineered protein is thermally stable and offers very high affinity and selectivity for uranyl with a Kd of 7.4 femtomolar (fM) and >10,000-fold selectivity over other metal ions. We also demonstrated that the uranyl-binding protein can repeatedly sequester 30-60% of the uranyl in synthetic sea water. The chemical strategy employed here may be applied to engineer other selective metal-binding proteins for biotechnology and remediation applications.

Positively charged phosphonate-functionalized mesoporous silica for efficient uranium sorption from aqueous solution

“…Naturally uranium reserves in the ocean, with low concentration (3.3 ppb) and dominant form of [UO 2 (CO 3 ) 3 ] 4− , is 1000 times more than that on land [2]. Therefore, it is strategically important to develop the effective methods for uranium extraction from seawater [3,4].…”

“…Among them, sorption offers several benefits such as simple operation, low cost, and easy recycling [10]. Various sorbents have been developed for potential uranium extraction from seawater, such as organic sorbents [11,12], inorganic sorbents [13,14], metal-organic frameworks [15], layered metal sulfides [14], engineered protein [3], nanoporous polymers [16], mesoporous carbons [17], ionimprinted composites [18,19] and graphene oxide composites [20]. Although a great progress has been achieved, there are still some challenges for uranium extraction from ocean.…”

Synthesis of polyamidoxime-functionalized nanoparticles for uranium(VI) removal from neutral aqueous solutions

“…The effects of solution pH (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12), adsorbent dose (15-125 mg/L), contact time (0-540 min), temperature and coexisting ions on uranium(VI) sorption were studied. The kinetic studies were performed at 298 K using 12.6 mg/L of uranium(VI) at pH 6.5; and the isotherm experiments were conducted using different initial concentrations of uranium(VI) solution (1.2-190.4 mg/L).…”

“…In the past decades, many methods have been developed for uranium(VI) removal from aqueous solutions [3][4][5][6][7][8][9][10][11] ,such as ionic exchange, chemical precipitation [12,13], membrane dialysis [14], flotation [15,16], bio-concentration [17], liquid-liquid extractions [18,19], solid-liquid separation [5,20,21]. At present, solid-liquid separation is recognized as the widest application prospect because it can work more efficiently and it is environment-friendly.…”

Surface functionalization graphene oxide by polydopamine for high affinity of radionuclides

“…Meanwhile, approximately 2300 tons of spent nuclear fuel are created during this process and this radionuclides such as 90-Sr 2+ , 137-Cs + , and UO 2 2+ , will pose a long-time threat to human living environment [1]. The safe treatment and disposal of radionuclides produced is a worldwide environmental concern, especially for uranium, which is the key element for nuclear energy [2,3]. A lot of uranium and its isotopes were released to the environment from nuclear manufacturing and processing, which posed a great threat to our living conditions due to their toxicity and radioactivity.…”