Premium
Structural insights into the mechanism of Type IVa pilus extension and retraction ATPase motors
Author(s) -
Solanki Vipul,
Kapoor Srajan,
Thakur Krishan Gopal
Publication year - 2018
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/febs.14619
Subject(s) - protein data bank (rcsb pdb) , pilus , geobacter sulfurreducens , chemistry , atp hydrolysis , atpase , biophysics , structural biology , crystallography , stereochemistry , biochemistry , biology , enzyme , escherichia coli , bacteria , biofilm , genetics , gene
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. Database Structural data are available in the RCSB PDB database under the PDB ID 5ZFQ (PilT‐4), 5ZFR (PilB).