Download MendeleyStructural insights into the mechanism of Type IVa pilus extension and retraction ATPase motors
Solanki, V., Kapoor, S., Thakur, K.G.(2018) FEBS J 285: 3402-3421
- PubMed: 30066435
- DOI: https://doi.org/10.1111/febs.14619
- Primary Citation of Related Structures:
5ZFQ, 5ZFR - PubMed Abstract:
Type IVa pili are bacterial appendages involved in diverse physiological processes, including electron transfer in Geobacter sulfurreducens. ATP hydrolysis coupled with conformational changes powers the extension (PilB) and retraction (PilT) motors in the pilus machinery. We report the unliganded crystal structures of the core ATPase domain of PilB and PilT-4 from G. sulfurreducens at 3.1 and 2.6 Å resolution, respectively. PilB structure revealed three distinct conformations, that is, open, closed, and open' which were previously proposed to be mediated by ATP/ADP binding. PilT-4 subunits, on the other hand, were observed in the closed state conformation. We further report that both PilB and PilT-4 hexamers have two high-affinity ATP-binding sites. Comparative structural analysis and solution data presented here supports the "symmetric rotary model" for these ATPase motors. Our data further suggest that pores of these motors rotate either clockwise or counterclockwise to facilitate assembly or disassembly of right-handed or left-handed pilus.
Organizational Affiliation:
Structural Biology Laboratory, G. N. Ramachandran Protein Centre, Council of Scientific and Industrial Research-Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India.
