Laser Light Scattering Determined Association of Deamidated betaB2–crystallins.

Abstract

Abstract: : Purpose: To determine the effect of deamidation on the structure and association of the betaB2–crystallin dimer. Two sites of deamidation were chosen that had previously been detected in whole soluble proteins from lenses of adult donors and that were located in important structural regions. Methods: Deamidations were introduced into recombinant betaB2 at Gln70 and Gln184 through site–directed mutagenesis. Gln70 is at the dimer interface and Q184 is at the tetramer interface. The associative properties of the betaB2 mutants were determined using static laser light scattering techniques. Results: All three recombinantly expressed betaB2s dimerized at the concentrations examined. No differences in associative properties were observed. Conclusions: Deamidation at Gln70 and Gln184 did not have an effect on betaB2 dimer, although this does not preclude an effect on higher–order oligimerization. This is in contrast to previously reported studies with the close betaB2 homolog, betaB1.

Keywords: crystallins • protein modifications–post translational • protein structure/function