Front Cover: Protein Structure Determination by Racemic and Quasi‐Racemic X‐Ray Crystallography (ChemBioChem 4/2026)

The Cover images shown here illustrate the diversity of protein molecular structures elucidated by crystallization of racemic and quasi-racemic protein mixtures. The protein structures range in size from rubredoxin (6 kDa) to a heterochiral protein complex of 36.5 kDa; they include proteins of novel cyclic covalent polypeptide topology, protein side chain-linked oligomers, homodimeric proteins, de novo designed proteins, and proteins of unprecedented secondary structure. Racemic and quasi-racemic protein mixtures facilitate formation of diffraction-quality crystals, simplify structure solution, and yield higher quality electron density maps. More details can be found in the Review Article by Stephen Kent (DOI: 10.1002/cbic.202500950).