Interaction and biophysical properties of human lens Q155* betaB2-crystallin mutant.
OBJECTIVE
Missense mutations in crystallin genes have been identified in autosomal dominant congenital cataracts. A truncation in the CRYBB2 gene (Q155*) has been associated with cerulean cataract, however its effects on biophysical properties have not been reported. We sought to determine the changes in conformation and protein-protein interactions brought about by this mutation.


METHODS
Site specific mutations were performed to obtain the Q155* betaB2-crystallin mutant. Protein-protein interactions were screened by a mammalian two-hybrid system assay. Conformational changes were studied with spectroscopy (circular dichroism and fluorescence) and FPLC chromatography.


RESULTS
We detected a decrease in protein-protein interactions for the Q155* betaB2-crystallin mutant. The Q155* mutant shows decreased ordered structure and stability but the partially unfolded protein retains some dimer structure.


CONCLUSIONS
The Q155* mutation in betaB2-crystallin causes changes in biophysical properties that might contribute to cataract formation.
Liu
Bing-Fen
BF
Center for Ophthalmic Research/Surgery, Brigham and Women's Hospital, Boston, MA 02115, USA.
Liang
Jack J-N
JJ
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D004591:Electrophoresis, Polyacrylamide Gel; D006367:HeLa Cells; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D020125:Mutation, Missense; D011485:Protein Binding; D011487:Protein Conformation; D020539:Sequence Analysis, Protein; D013050:Spectrometry, Fluorescence; D014162:Transfection; D020798:Two-Hybrid System Techniques; D038206:beta-Crystallin B Chain / Q000737:chemistry* / Q000235:genetics
D038206:beta-Crystallin B Chain; C113634:beta-crystallin B2