Structural, functional and immunologic characterization of folded subdomains in the Ro52 protein targeted in Sjögren's syndrome

摘要: Ro52, one of the major autoantigens in rheumatic disease Sjogren's syndrome (SS), belongs to tripartite motif (TRIM) or RING-B-box-coiled-coil (RBCC) protein family, thus comprising an N-terminal RING, followed by a B-box and coiled-coil region. Several different proteomic functions have been suggested for including DNA binding, interactions Zn(2+)-binding. To analyze presence and/or absence these and, particular, map those subregions, modular composition Ro52 was experimentally characterized. Two structured parts were identified, corresponding RING-B-box regions, respectively. Secondary structure analysis circular dichroism (CD) spectroscopy indicated that two subregions are independently structured. The entire region displayed Zn(2+)-dependent stabilization against proteolysis Zn2+, indicating functional Zn(2+)-binding sites both RING B-box. However, no with detected, irrespective Zn(2+), suggesting does not bind DNA. Oligomerization investigated analytical ultracentrifugation mammalian two-hybrid system. Both methods show weak homodimer affinity, parity other domains involved regulatory interactions. C-terminal B30.2 rapidly degraded during cellular expression refolding, less stable structure. Immunologic regions sera from patients shows immunodominant epitopes large extent localized structurally Ro52. results form basis further studies on proteome level.