Nucleus-Encoded Protein BFA1 Promotes Efficient Assembly of the Chloroplast ATP Synthase Coupling Factor 1.
Zhang, L., Pu, H., Duan, Z., Li, Y., Liu, B., Zhang, Q., Li, W., Rochaix, J.D., Liu, L., Peng, L.(2018) Plant Cell 30: 1770-1788
- PubMed: 30012777 
- DOI: https://doi.org/10.1105/tpc.18.00075
- Primary Citation of Related Structures:  
5YVF - PubMed Abstract: 
F-type ATP synthases produce nearly all of the ATP found in cells. The catalytic module F 1 commonly comprises an α 3 β 3 hexamer surrounding a γ/ε stalk. However, it is unclear how these subunits assemble to form a catalytic motor. In this work, we identified and characterized a chloroplast protein that interacts with the CF 1 β, γ, and ε subunits of the chloroplast ATP synthase and is required for assembly of its F 1 module. We named this protein BIOGENESIS FACTOR REQUIRED FOR ATP SYNTHASE1 (BFA1) and determined its crystal structure at 2.8-Å resolution. BFA1 is comprised primarily of two interacting β-barrels that are oriented nearly perpendicularly to each other. The contact region between BFA1 and the CF 1 β and γ subunits was further mapped by yeast two-hybrid assays. An in silico molecular docking analysis was performed and revealed close fitting contact sites without steric conflicts between BFA1 and CF 1 β/γ. We propose that BFA1 acts mainly as a scaffold protein promoting the association of a CF 1 α/β heterodimer with CF 1 γ. The subsequent assembly of other CF 1 α/β heterodimers may shift the position of the CF 1 γ subunit to complete assembly of the CF 1 module. This CF 1 assembly process is likely to be valid for other F-type ATP synthases, as their structures are highly conserved.
Organizational Affiliation: 
College of Life and Environmental Sciences, Shanghai Normal University, Shanghai 200234, China.