Investigation of the conformational states of Wzz and the Wzz.O-antigen complex under near-physiological conditions.
Investigation of the conformational states of Wzz and the Wzz.O-antigen complex under near-physiological conditions.
复制标题
在接近生理条件下研究 Wzz 和 Wzz.O-抗原复合物的构象状态。
DOI：
10.1021/bi701181r
复制
发表时间：
2007
期刊：
影响因子：
2.9
通讯作者：
Wang,PengGeorge
中科院分区：
文献类型：
--
作者：
Tang,Kuo-Hsiang;Guo,Hongjie;Yi,Wen;Tsai,Ming-Daw;Wang,PengGeorge
Chain length determinant protein (Wzz) has been postulated to terminate the polymerization and regulate the chain length of the O-polysaccharide (O-antigen), an important component for constructing lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria. The investigation to understand the mechanism of Wzz has been largely slowed down due to lack of structural information. In this report, we have applied small-angle X-ray scattering (SAXS) to study the conformational state and molecular properties of Wzz and the Wzz·O-antigen complex under near-physiological conditions. No concentration-dependent aggregation or structural changes, but repulsive intermolecular interactions between Wzz molecules, are suggested in the concentration series studies. The SAXS studies suggest that Wzz protein appears to be elongated and exists as a tetramer in solution. The reconstructed model built from SAXS data indicates that the middle regime of Wzz, most likely representing the periplasmic domain, contributes to the Wzz oligomerization, which has been proposed to be correlated to the function of Wzz. The immunoblotting analyses also demonstrate that the putative coiled-coil region in the periplasmic region contributes to the oligomerization. Further, the SAXS data corresponding to Wzz and the Wzz·O-antigen complex indicate an apparent substrate (O-antigen)-induced conformational change, consistent with previous circular dichroism studies. Our finding may shed light on the biological mechanism of Wzz as a chain length determinant of O-antigen.
