Orthogonal Protein Heterodimers With Modular Binding Specificity
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Solution Overview
Problem
Current protein-protein interaction specificity is challenging to generalize due to backbone shape complementarity, which is less modular compared to DNA-DNA and protein-DNA interactions, limiting the ability to create orthogonal protein heterodimers for bioengineering applications.
Innovation Solution
Designing heterodimer proteins composed of non-naturally occurring polypeptides with specific sequence identities and hydrogen bond networks, allowing for modular and orthogonal interactions by forming heterodimers through amino acid linkers and hydrogen bond networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backbone shape complementarity is used to achieve protein-protein interaction specificity, then interaction specificity is achieved, but modularity and generalizability are reduced
Solution Approach 1:
The protein interaction interface is segmented into two independent modules: a backbone module that provides structural framework and a side chain module that provides specific recognition. The backbone uses a standardized coiled-coil structure with fixed geometry, while the side chains at the interface are independently optimized for specific cognate recognition. This segmentation allows the backbone to be general and modular while the side chains provide specific binding affinity.
Solution Approach 2:
A universal backbone structure (coiled-coil motif) is designed that can serve as a platform for multiple different specific interactions. The standardized backbone geometry and hydrophobic core provide a consistent framework that can be combined with various side chain configurations to create multiple orthogonal heterodimer pairs, enabling generalizability across different protein pairs.
2Adaptability or versatility
If standardized backbone structures with modular side chains are used, then modularity and generalizability are improved, but interaction specificity must be maintained through careful design
Solution Approach 1:
While the backbone structure is standardized and uniform, the side chains at the interaction interface are locally optimized with specific amino acid compositions and geometries. This creates local chemical diversity and specific recognition patterns at the binding interface, ensuring high specificity for cognate partners while maintaining overall structural modularity.
Solution Approach 2:
The heterodimer interface is designed with asymmetric side chain distributions where monomer A and monomer B have complementary but non-identical side chain patterns. This asymmetry ensures directional and specific recognition where A binds B but not A:A or B:B homodimers, maintaining interaction specificity within the modular framework.
3Adaptability or versatility
If non-naturally occurring polypeptides with specific sequence identities are designed, then orthogonal heterodimer formation is enabled, but design complexity increases
Solution Approach 1:
The design systematically varies specific parameters including hydrophobic core residues, interface side chain compositions, and linker sequences to generate orthogonal heterodimer pairs. By controlling and optimizing these parameters within defined ranges, the invention enables systematic generation of multiple specific interactions while following standardized design rules that reduce overall complexity.
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
Enables the creation of a wide range of heterodimeric interaction specificities, facilitating the design of protein-based logic gates and synthetic biology applications by ensuring selective cognate pair formation and avoiding non-cognate interactions.
Implementation Method 1
asymmetric buried hydrogen bond networks incorporated into regularly repeating backbone structures
Implementation Method 2
monomer A and monomer B non-covalently interact to form the designed heterodimer protein
Data Source
AI summary
Disclosed herein are designed heterodimer proteins, monomeric polypeptides capable of forming heterodimer proteins, protein scaffolds including such polypeptides, and methods for using the heterodimer proteins and subunit polypeptides for designing logic gates.