Crystallins are the dominant structural components of the vertebrate eye lens. Homo/heterodimer, or complexes of higher-order. The structure of beta-crystallin oligomers seems to be stabilized through interactions between the N-terminal arms. Has a two-domain beta-structure, folded into four very similar Greek key motifs. Specific cleavages in the N-terminal arm occur during lens maturation and give rise to truncated forms, leading to impaired oligomerization and protein insolubilization. The protease responsible for this partial degradation could be calpain II. Belongs to the beta/gamma-crystallin family.