Study of subunit interactions of alpha A- and alpha B-crystallins and the effects of gamma-irradiation on their interactions by surface plasmon resonance.
Alpha-crystallin, a major protein of mammalian lens, consists of two subunits, alpha A-crystallin and alpha B-crystallin. They interact to form an aggregate and play a prominent role in the maintenance of lens transparency. We evaluated the interaction between these subunits via surface plasmon resonance (SPR) using four combinations of immobilized protein and analyte: 1) AA: alpha A-crystallin was ligand immobilized onto the sensor and alpha A-crystallin was passed over the ligand, 2) AB: ligand - alpha A-crystallin, analyte - alpha B-crystallin, 3) BB: ligand - alpha B-crystallin, analyte- alpha B-crystallin, 4) BA: ligand - alpha B-crystallin, analyte - alpha A-crystallin. The order of rate of dissociation was AA approximately BA>BB approximately AB. We also examined the dissociation of gamma irradiated alpha A- and alpha B-crystallins. As radiation dose increased, so did the dissociation rate of all of the crystallins. The order of rate of dissociation of irradiated crystallins was BB>AB approximately BA>AA. The results indicate that BB is the most susceptible to gamma-irradiation and that alpha B-crystallin forms a more stable aggregate than alpha A-crystallin under normal conditions. However, when alpha B is irradiated the aggregate becomes unstable.
Fujii
Norihiko
N
Department of Chemistry Graduate School of Science Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan. nfujii@HL.rri.kyoto-u.ac.jp
Hisano
Tamao
T
Fujii
Noriko
N
D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006801:Humans; D011485:Protein Binding / Q000528:radiation effects; D021122:Protein Subunits / Q000378:metabolism / Q000528:radiation effects; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D020349:Surface Plasmon Resonance; D038202:alpha-Crystallin A Chain / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects; D038203:alpha-Crystallin B Chain / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism* / Q000528:radiation effects
D021122:Protein Subunits; D011994:Recombinant Proteins; D038202:alpha-Crystallin A Chain; D038203:alpha-Crystallin B Chain