Near-Infrared Optical Switch Proteins for Reliable Binding Control
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Solution Overview
Problem
Existing photoswitching proteins, such as RpBphP1 and RpPpsR2, have difficulty in reliably controlling binding and dissociation with near-infrared light due to spontaneous binding in the dark, limiting their effectiveness in biological applications.
Innovation Solution
Development of RpBphP1 and RpPpsR2 mutants with specific amino acid mutations and modifications that allow controlled binding and dissociation through near-infrared light irradiation, including combinations of wild-type and mutant proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If wild-type RpBphP1 and RpPpsR2 are used for photoswitching, then near-infrared light permeability is improved, but reliable control of binding and dissociation deteriorates due to spontaneous binding in the dark
Solution Approach 1:
The patent applies parameter changes by introducing specific amino acid mutations (e.g., Q502A, E513A in RpBphP1; Q105T, L137E in RpPpsR2) to alter the binding affinity parameters of the protein pair. These mutations modify the interaction characteristics between RpBphP1 and RpPpsR2, enabling reliable light-controlled binding and dissociation while maintaining near-infrared light permeability. The mutations change the energy landscape of the protein-protein interaction to achieve switchable binding behavior.
2Reliability
If blue light is used for photoswitching, then binding control is achieved, but tissue penetration capability deteriorates due to hemoglobin absorption
Solution Approach 1:
The patent changes the light wavelength parameter from blue light (470 nm or less) to near-infrared light (650-900 nm) to avoid hemoglobin absorption. This parameter change in light wavelength maintains the photoswitching functionality while eliminating the harmful absorption effect of hemoglobin, enabling deep tissue penetration for in vivo applications.
Solution Approach 2:
The patent substitutes the blue light activation mechanism with a near-infrared light activation mechanism. This replacement involves using a different photoreceptor system (RpBphP1-RpPpsR2 pair) that responds to near-infrared light instead of blue light, thereby replacing the optical activation mechanism to avoid hemoglobin interference while maintaining photoswitching capability.
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
The mutant proteins enable reliable control of binding and dissociation with near-infrared light, enabling applications in living organisms by ensuring binding is weaker in the dark and stronger under near-infrared light.
Implementation Method 1
a protein set consisting of two proteins that bind to each other under near-infrared light irradiation... the binding of the protein set is weaker under the dark and/or is stronger under near-infrared light irradiation
Data Source
AI summary
It is an object of the present invention to provide an RpBphP1 mutant and an RpPpsR2 mutant that have been improved so that their binding and dissociation can be reliably controlled by light irradiation with a near-infrared light and blocking thereof. More specifically, the present invention relates to a protein set consisting of two proteins that bind to each other under near-infrared light irradiation, the protein set being a set of an RpBphP1 mutant and a wild-type RpPpsR2, a set of a wild-type RpBphP1 and an RpPpsR2 mutant, or a set of an RpBphP1 mutant and an RpPpsR2 mutant, wherein the binding of the protein set is weaker under the dark and/or is stronger under near-infrared light irradiation, than the binding of a wild-type RpBphP1 and a wild-type RpPpsR2.