EM Grid Linker Geometry for Broader Analyte Orientation
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Solution Overview
Problem
Existing electron microscopy and cryo-electron microscopy methods face challenges in achieving optimal angular distribution of analytes on grids, leading to suboptimal orientation and increased image acquisition time, especially for smaller analytes, which limits high-resolution structural determination.
Innovation Solution
The use of electron microscopy grids with a mixture of linker molecules, each with unique angled and linear linker sections, forces analytes into multiple orientations, maximizing angular distribution and reducing the need for tilt adjustments during imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single type of linker with flexible spacer is used to increase flexibility and angular distribution, then flexibility is improved, but analytes still tend to orient in a similar way and preferred orientation is not prevented
Solution Approach 1:
The patent divides the linker population into multiple segments with distinct geometries. Instead of using a single flexible linker type, the invention employs a mixture of linkers where each linker has a specific combination of rigid and flexible sections with defined angles and lengths. This segmentation of the linker population creates diverse anchoring geometries that force analytes into different orientations, reliably preventing preferred orientation.
Solution Approach 2:
The patent introduces asymmetry in linker geometry by incorporating rigid sections at specific angles (e.g., 30°, 45°, 60°, 90°, 120°, 135°, 150°, or 180° relative to the support film) combined with flexible spacers of varying lengths. This asymmetric geometric design ensures that each linker type imposes a preferred but different orientation on bound analytes, collectively achieving uniform angular distribution across the grid surface.
2Adaptability or versatility
If tilt adjustments are made between images to increase angular distribution, then angular coverage is improved, but focus plane changes reduce contrast of off-axis particles and image quality deteriorates
Solution Approach 1:
The patent performs preliminary action by pre-orienting analytes into multiple angles during sample preparation on the grid, before imaging begins. The mixture of linkers with different geometries is applied to the support film, and analytes are allowed to bind in various orientations during this preparation phase. This preliminary angular distribution eliminates the need for subsequent tilt adjustments during imaging, maintaining optimal focus and contrast throughout data collection.
3Reliability
If multiple screening conditions and approaches are tested to achieve optimal orientation, then orientation quality may be improved, but the process becomes tedious and time-consuming
Solution Approach 1:
The patent creates a universal solution that works across different analyte types without requiring tedious screening. The mixture of linkers with diverse geometries provides a multi-functional platform that can accommodate various analyte shapes, sizes, and binding characteristics. This universal approach eliminates the need to optimize separate conditions for each analyte, as the geometric diversity of the linker mixture inherently provides robust angular distribution for different molecular targets.
Solution Approach 2:
The patent systematically varies geometric parameters of the linkers (rigid section angles, flexible spacer lengths, and linker compositions) to create a standardized mixture that provides reliable angular distribution. By pre-defining these geometric parameters across multiple linker types, the invention establishes a standardized protocol that achieves optimal orientation quality without requiring empirical screening for each new analyte.
4Length of moving object
If long linkers are used to increase flexibility, then flexibility is improved, but analytes still orient in a similar way and preferred orientation is not prevented
Solution Approach 1:
The patent creates a composite linker system by combining multiple linker types with different geometric characteristics in a single mixture. Each linker in the mixture contains a specific combination of rigid sections (with defined angles) and flexible spacers (of defined lengths). This composite approach leverages the strengths of both rigid and flexible components, where the rigid sections provide angular diversity while the flexible spacers provide adaptability, achieving superior angular distribution compared to using long flexible linkers alone.
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 enhances image resolution by increasing the number of usable projection angles, reduces image acquisition time, and allows for high-throughput structural analysis without the need for tedious screening processes or additional additives.
Implementation Method 1
AG is an anchoring group, for anchoring the linker molecule to the support film
Implementation Method 2
BU is a binding unit, for binding to the analyte
Data Source
AI summary
The invention provides in an electron microscopy grid, comprising: a perforated substrate; a support film on the perforated substrate; a mixture of different linker molecules according to Structure (I), wherein AG is an anchoring group, for anchoring the linker molecule to the solid support; BU is a binding unit, for binding to the analyte; L1 is a first linear linker section; L2 is a second linear linker section; α is the angle between the linear linker section L1 and the linear linker section L2; AS is an angled linker section, connecting the linear linker section L1 and the linear linker section L2. The invention further provides in method of structural determination of analytes, using such EM-grids.