Fluorescence polarization studies of fluorescein isothiocyanate conjugates of bovine lens crystallins.
Bovine lens alpha-, beta H- and gamma-crystallin were labeled with the amine-specific fluorescent probe, fluorescein isothiocyanate (FITC) and studied with steady-state polarization measurements. Rotational relaxation times (rho) were estimated for various crystallins and were compared with calculated values. The observed rho value is considerably faster for alpha- and beta H-crystallin conjugate than the calculated value, indicating existence of a segmental motion of the probe on these two crystallins. The segmental flexibility may result from a less tightly folded structure in these crystallins. alpha-Crystallin isolated from the cow lens nucleus shows a smaller rho value than the young cortical alpha-crystallin. The protein partial unfolding process appears to be age-related, and a possible consequence is that crystallin becomes more susceptible to chemical modifications.
D000818:Animals; D002417:Cattle; D003459:Crystallins / Q000032:analysis*; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005454:Fluorescence Polarization; D005456:Fluorescent Dyes; D011487:Protein Conformation; D013861:Thiocyanates
D003459:Crystallins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D013861:Thiocyanates; D016650:Fluorescein-5-isothiocyanate