Crystal structure of human WBSCR16, an RCC1-like protein in mitochondria

Title: Crystal structure of human WBSCR16, an RCC1-like protein in mitochondria Authors: Koyama, Masako; Sasaki, Taeko; Sasaki, Narie; Matsuura, Yoshiyuki Abstract: WBSCR16 (Williams-Beuren Syndrome Chromosomal Region 16) gene is located in alarge deletion region of Williams-Beuren syndrome (WBS), which is a neurodevelopmental disorder.Although the relationship between WBSCR16 and WBS remains unclear, it has been reported thatWBSCR16 is a member of a functional module that regulates mitochondrial 16S rRNA abundanceand intra-mitochondrial translation. WBSCR16 has RCC1 (Regulator of Chromosome Condensation1)-like amino acid sequence repeats but the function of WBSCR16 appears to be different fromthat of other RCC1 superfamily members. Here, we demonstrate that WBSCR16 localizes to mito-chondria in HeLa cells, and report the crystal structure of WBSCR16 deter mined to 2.0 A˚resolutionusing multi-wavelength anomalous diffraction. WBSCR16 adopts the seven-bladed b-propeller foldcharacteristic of RCC1-like proteins. A comparison of the WBSCR16 structure with that of RCC1and other RCC1-like proteins reveals that, although many of the residues buried in the core of theb-propeller are highly conserved, the surface residues are poorly conserved and conformationally divergent.