Key wordY: c~-Crystallin; Chaperone; y-Crystallin; Lens y-B crystallin (formerly y-II) [9] are used to explain, on the molecular level, recent experimental observations [10,11]. The data show that c~-crystallin binds to partially heat denatured soluble 7/-crystallin in a 1 : I monomer stoichiometry. This binding protects y-crystallin from further heat induced thermal denaturation [10] as well as thiol oxidation [11]. Wang and Spector [10] suggest that each monomer in ~-crystallin binds a soluble, partially denatured y-crystallin molecule at a single binding site. The 1 : 1 ratio has also been reported by Borkman et al. [12] for the ~/y complex following UV radiation. Using our quaternary model for simulation of these observations, the results show that y-crystallin N-terminal domain is intercalated in the space between the adjacent C-terminal domains of ~-crystallin subunits.