Structure of the essential diversity-generating retroelement protein bAvd and its functionally important interaction with reverse transcriptase.Alayyoubi, M., Guo, H., Dey, S., Golnazarian, T., Brooks, G.A., Rong, A., Miller, J.F., Ghosh, P.
(2013) Structure 21: 266-276
- PubMed: 23273427
- DOI: 10.1016/j.str.2012.11.016
- Primary Citation of Related Structures:
- PubMed Abstract:
Diversity-generating retroelements (DGRs) are the only known source of massive protein sequence variation in prokaryotes. These elements transfer coding information from a template region (TR) through an RNA intermediate to a protein-encoding variable region ...
Diversity-generating retroelements (DGRs) are the only known source of massive protein sequence variation in prokaryotes. These elements transfer coding information from a template region (TR) through an RNA intermediate to a protein-encoding variable region. This retrohoming process is accompanied by unique adenine-specific mutagenesis and, in the prototypical BPP-1 DGR, requires a reverse transcriptase (bRT) and an accessory variability determinant (bAvd) protein. To understand the role of bAvd, we determined its 2.69 Å resolution structure, which revealed a highly positively charged pentameric barrel. In accordance with its charge, bAvd bound both DNA and RNA, albeit without a discernable sequence preference. We found that the coding sequence of bAvd functioned as part of TR but identified means to mutate bAvd without affecting TR. This mutational analysis revealed a strict correspondence between retrohoming and interaction of bAvd with bRT, suggesting that the bRT-bAvd complex is important for DGR retrohoming.
Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA.