Beta Roll Peptides for Rare Earth Element Binding
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Solution Overview
Problem
The recovery of rare earth elements (REEs) from natural and man-made sources is hindered by their low concentrations and the difficulty in isolating them from other metals, with existing methods being inefficient, particularly lanmodulin which can only bind three REE ions per protein, limiting industrial-scale effectiveness.
Innovation Solution
A method involving the use of polypeptides with repeats-in-toxin (RTX) domains that form beta-roll structures, which bind REEs and induce a conformational change, allowing for the formation of metal-peptide complexes that can be isolated and precipitated, particularly using a specific amino acid sequence and acidic conditions to enhance REE binding and separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If lanmodulin protein is used to bind REE ions, then binding specificity is improved, but binding capacity is limited to three REE ions per protein
Solution Approach 1:
The invention divides the binding function into multiple independent beta roll domains within a single polypeptide chain. Each domain can bind REE ions independently, allowing the protein to bind multiple REE ions simultaneously. This segmentation of the binding sites resolves the contradiction between specificity (maintained through each domain's selective binding) and capacity (increased through multiple domains).
Solution Approach 2:
The polypeptide chain performs multiple binding functions through its multiple beta roll domains. Instead of a single-domain protein that binds only one or three REE ions, the multi-domain structure enables the protein to bind multiple REE ions with high specificity, effectively increasing both capacity and specificity simultaneously.
2Productivity
If conventional REE recovery methods are used, then process simplicity is maintained, but recovery efficiency is low due to low REE concentrations and difficulty in isolation
Solution Approach 1:
The invention replaces conventional mechanical or chemical separation methods with a biological recognition system. The polypeptide's beta roll domains selectively bind REE ions through specific molecular interactions, enabling efficient recovery from complex matrices like e-waste and mining wastes without requiring complex mechanical separation processes.
Solution Approach 2:
The polypeptide acts as an intermediary between the REE ions in the sample and the recovery process. By providing specific binding sites that recognize and bind REE ions, the polypeptide facilitates selective recovery from complex mixtures, improving efficiency while keeping the overall process relatively simple.
3Measurement precision
If beta roll domains are used to bind metals, then binding selectivity for specific metals is achieved, but effectiveness at binding all metals or metal compounds is limited
Solution Approach 1:
Each beta roll domain is designed with specific local chemical properties that enable selective binding of REE ions. The conserved amino acid sequences create localized binding sites with specific coordination chemistry preferences, allowing high selectivity for REEs while maintaining the ability to bind multiple different REE types through multiple domains.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables the selective and efficient recovery of REEs from sources like e-wastes and mining wastes, offering a higher binding capacity and selectivity compared to existing methods, facilitating the extraction of REEs for use in clean energy technologies.
Implementation Method 1
binding an amount of the metal component to the polypeptide to form a metal-peptide complex includes inducing a conformational change in the polypeptide from a disordered conformation to a beta-roll secondary structure
Implementation Method 2
the method includes precipitating the metal-peptide complex from the solution. In some embodiments, the pH of the solution is below about 3. In some embodiments, the pH of the solution is below about 1.5
Data Source
AI summary
Rare earth elements (REEs) are recovered by dissolving an REE-containing source in one or more solvents. The resulting solution is contacted with block V repeats-in-toxin (RTX) domains of adenylate cyclase from Bordetella pertussis. These polypeptides are generally intrinsically disordered. However, upon binding an amount of the REEs and/or REE-containing compounds, the polypeptide folds to form a beta roll (BR) secondary structure. The polypeptides also adopt the BR structure at very low pH, e.g., below about 1.5, yet are still capable of effectively binding REEs. The metal-peptide constructs can then be isolated for recovery of REE products. Native and synthetic RTX/BR domains can be used to bind and recover REEs with higher binding capacity than lanmodulin and enhanced REE selectivity. For example, embodiments of the present disclosure can be used to extract REEs from electronic wastes such as NdFeB magnets, seaweed ashes, used during biomining and bioleaching operations, etc.