SAXS and SANS observations of abnormal aggregation of human alpha-crystallin.
Aggregation states of human alpha-crystallins are observed complementarily using small-angle X-ray and small-angle neutron scatterings (SAXS and SANS). Infant alpha-crystallin is almost a monodispersed system of the aggregates with gyration radius of ca. 60 A, which is a normal aggregate. On the other hand, the aged and cataract alpha-crystallins have not only the normal but also the larger aggregates. In the aged alpha-crystallin, the normal aggregate is a major component, but in the cataract alpha-crystallin the larger ones are dominant. Both alpha A- and alpha B-crystallins, which are subunits of alpha-crystallin, also form an aggregate with the size close to the normal aggregate. Under UV irradiation, only aggregates of alpha B-crystallin undergo further aggregation. Therefore, considering increase of ratio of alpha B-crystallin in the aggregate of alpha-crystallin as aging, the abnormal aggregation (formation of the huge aggregates) mainly results in the further aggregation of alpha B-crystallin caused by external stresses.
Sugiyama
Masaaki
M
Research Reactor Institute, Kyoto University, Osaka 590-0494, Japan.
Fujii
Norihiko
N
Morimoto
Yukio
Y
Itoh
Keiji
K
Mori
Kazuhiro
K
Fukunaga
Toshiharu
T
Fujii
Noriko
N
D000368:Aged; D000375:Aging; D002386:Cataract / Q000378:metabolism; D006801:Humans; D007223:Infant; D033363:Neutron Diffraction; D053838:Scattering, Small Angle; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction; D038202:alpha-Crystallin A Chain / Q000737:chemistry / Q000528:radiation effects; D038203:alpha-Crystallin B Chain / Q000737:chemistry / Q000528:radiation effects; D038201:alpha-Crystallins / Q000737:chemistry* / Q000378:metabolism
D038202:alpha-Crystallin A Chain; D038203:alpha-Crystallin B Chain; D038201:alpha-Crystallins