Details

Autor(en) / Beteiligte

• Sun, Tian-Xiao
• Liang, Jack J.-N.

Titel

Intermolecular Exchange and Stabilization of Recombinant Human αA- and αB-Crystallin

Ist Teil von

• The Journal of biological chemistry, 1998-01, Vol.273 (1), p.286-290

Ort / Verlag

Elsevier Inc

Erscheinungsjahr

1998

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Lens α-crystallin subunits αA and αB are differentially expressed and have a 3-to-1 ratio in most mammalian lenses by intermolecular exchange. The biological significance of this composition and the mechanism of exchange are not clear. Preparations of human recombinant αA- and αB-crystallins provide a good system in which to study this phenomenon. Both recombinant αA- and αB-crystallins are folded and aggregated to the size of the native α-crystallin. During incubation together, they undergo an intermolecular exchange as shown by native isoelectric focusing. Circular dichroism measurements indicate that the protein with a 3-to-1 ratio of αA- and αB-crystallins has the same secondary structure but somewhat different tertiary structures after exchange: the near-UV CD increases after exchange. The resulting hybrid aggregate is more stable than the individual homogeneous aggregates: at 62 °C, αB-crystallin is more susceptible to aggregation and displays a greater light scattering than αA-crystallin. This heat-induced aggregation of αB-crystallin, however, was suppressed by intermolecular exchange with αA-crystallin. These phenomena are also observed by fast performance liquid chromatography gel filtration patterns. The protein structure of αB-crystallin is stabilized by intermolecular exchange with αA-crystallin.