Pathological macromolecular crystallographic data affected by twinning, partial-disorder and exhibiting multiple...

Area of Science:

• Crystallography
• Structural Biology
• Enzymology

Background:

• Crystal twinning is a common anomaly in macromolecular crystallography (MX), complicating structural analysis.
• Existing methods often involve re-screening for crystallization conditions or collecting data from untwinned crystal regions.
• Successfully processing twinned data remains a significant challenge in determining protein structures.

Purpose of the Study:

• To report the successful determination and deposition of 11 structures of engineered E. coli N-acetyl-neuraminic lyase variants.
• To present high-resolution structural data (1.45-2.30 Å) from crystals exhibiting twinning and incommensurate modulation.
• To offer a challenging dataset for the advancement of MX data processing software.

Main Methods:

• Macromolecular crystallography (MX) data collection and processing.
• Structure determination and refinement of 11 enzyme variants.
• Indexing and solving of datasets with significant lattice disorder.

Main Results:

• 11 structures of engineered E. coli N-acetyl-neuraminic lyase variants were successfully solved and deposited.
• The determined structures achieved high resolution (1.45-2.30 Å) despite crystal twinning and modulation.
• The processed data represent a unique test set for MX data processing algorithms.

Conclusions:

• It is possible to determine high-resolution structures from twinned and modulated crystals in MX.
• The reported structures serve as a valuable benchmark for validating and improving MX data processing tools.
• This work demonstrates the potential for overcoming significant crystallographic challenges to obtain crucial structural information.