TY - JOUR CY - 2 ABBEY SQ, CHESTER, CH1 2HU, ENGLAND N1 - Copyright of this article belongs to INT UNION CRYSTALLOGRAPHY. ID - open2586 UR - https://journals.iucr.org/m/issues/2020/04/00/lz5036/ IS - 4 A1 - Choukate, Komal A1 - Chaudhuri, Barnali Y1 - 2020/07/08/ N2 - Wag31, or DivIVA, is an essential protein and a drug target in the human pathogen Mycobacterium tuberculosis that self-assembles at the negatively curved membrane surface to form a higher-order structural scaffold, maintains rod-shaped cellular morphology and localizes key cell-wall synthesizing enzymes at the pole for exclusive polar growth. The crystal structure of the N-terminal lipid-binding domain of mycobacterial Wag31 was determined at 2.3 angstrom resolution. The structure revealed a highly polar surface lined with several conserved charged residues that suggest probable sites for interactions with membrane lipids. Crystal-packing analysis revealed a previously unseen `dimer-of-dimers' assembly state of N-terminal Wag31, which is formed by antiparallel stacking of two coiled-coil dimers. Size-exclusion column-chromatography-coupled small-angle solution X-ray scattering data revealed a tetrameric form as a major assembly state of N-terminal Wag31 in solution, further supporting the crystal structure. The results suggest that, in addition to lipid binding, the N-terminal Wag31 can participate in self-assembly to form filamentous structures. Plausible models of linear self-assembly and branching of Wag31 filaments consistent with available data are suggested. PB - INT UNION CRYSTALLOGRAPHY JF - IUCRJ VL - 7 KW - mycobacterial polar growth; dimer assembly; mycobacterium tuberculosis; coiled coil; lipids; filaments TI - Structural basis of self-assembly in the lipid-binding domain of mycobacterial polar growth factor Wag31 SP - 767 EP - 776 ER -