Calf lens alpha-crystallin, a molecular chaperone, builds stable complexes with beta s- and gamma-crystallins

Calf water-soluble (WS) crystallins consist of high-molecular weight (HM), alpha-, beta H-, beta L-, beta s- and gamma-crystallins. alpha-Crystallin as a molecular chaperone forms a structure with a central hole, known as Carver's model. The only crystallins fitting into this central cavity are beta s- and gamma-crystallins, with native molecular weights of 28 and 18.5-21 kD, respectively. The beta s-crystallin is loosely bound to this structure, whereas with the application of 7M urea in the sample, beta s-, may be some beta L-components and all gamma-crystallins emerge from the central hole. Although WS and water-insoluble (WI) crystallins display the same immunologic determinants, there is an appreciable difference in electrophoretic mobility already in the young calf lens. alpha-Crystallins from the WI part demonstrate a clear cathodic shift. WI beta- and gamma-crystallins show smaller but well perceptible cathodic shifts. The chaperone function of alpha-crystallin preserves the original structures of beta s- and gamma-crystallins for aggregation and other influences.