Eliminating the Missing Cone Challenge through Innovative Approaches

Area of Science:

• Structural biology
• Biophysics
• Crystallography

Background:

• Microcrystal electron diffraction (MicroED) is vital for determining molecular structures from small crystals.
• Plate-like crystals often exhibit preferred orientation on microscopy grids, leading to a 'missing cone' of data.
• This orientation limitation restricts the completeness of structural information obtainable via MicroED.

Approach:

• Introduced suspended drop crystallization as a novel strategy to address preferred crystal orientation.
• Demonstrated the efficacy of this method using two distinct plate-like crystal samples: bovine liver catalase and COVID-19 main protease (Mpro).

Key Points:

• Suspended drop crystallization effectively eliminates the missing cone of data in MicroED.
• Successfully determined complete structures from plate-like crystals that previously posed orientation challenges.
• The method is particularly beneficial for samples that naturally crystallize as thin plates.

Conclusions:

• Suspended drop crystallization is an indispensable technique for overcoming preferred orientation in MicroED.
• This approach significantly enhances the scope and success rate of MicroED structure determination.
• Enables comprehensive structural analysis for challenging crystal morphologies.