Brucella Immunogenic BP26 Forms a Channel-like Structure.
Kim, D., Park, J., Kim, S.J., Soh, Y.M., Kim, H.M., Oh, B.H., Song, J.J.(2013) J Mol Biol 425: 1119-1126
- PubMed: 23353825 
- DOI: https://doi.org/10.1016/j.jmb.2013.01.015
- Primary Citation of Related Structures:  
4HVZ - PubMed Abstract: 
An outer membrane protein BP26/OMP28 of Brucella, BP26, is identified as a major immunodominant antigen and widely used as a diagnostic marker and for vaccination against Brucellosis. BP26 belongs to the family of proteins that contains a SIMPL (signaling molecule that associates with the mouse pelle-like kinase) domain, whose structure and function have been unknown. Here, we present the crystal structure of BP26 revealing that 16 BP26 molecules form a novel channel-like assembly as also shown by electron microscopy analysis. Eight BP26 molecules forming a ring structure contain a hole at the center of the octamer, and another octamer interacts with each other to form a channel having a large internal cavity. BP26 is found to be structurally similar to a bacteriophage protein involved in infection, implicating that BP26 might function during Brucella infection. In addition, the BP26 structure suggests that the protein functions as a multimeric channel-like form and provides a canonical model for the SIMPL domains.
Organizational Affiliation: 
Department of Biological Sciences, KI for the BioCentury, KAIST, 335 Gwahangno, Daejeon 305-701, Korea.