PDBsum entry 2gsz

Protein transport

PDB id: 2gsz

Contents

Protein chains

(+ 0 more) 343 a.a. *

Ligands

SO4 ×3

ADP

* Residue conservation analysis

PDB id:

2gsz

Name:

Protein transport

Title:

Structure of a. Aeolicus pilt with 6 monomers per asymmetric unit

Structure:

Twitching motility protein pilt. Chain: a, b, c, d, e, f. Engineered: yes

Source:

Aquifex aeolicus. Organism_taxid: 63363. Gene: pilt. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

4.20Å R-factor: 0.346 R-free: 0.406

Authors:

K.T.Forest,K.A.Satyshur

Key ref:

K.A.Satyshur et al. (2007). Crystal structures of the pilus retraction motor PilT suggest large domain movements and subunit cooperation drive motility. Structure, 15, 363-376. PubMed id: 17355871 DOI: 10.1016/j.str.2007.01.018

Date:

27-Apr-06 Release date: 20-Mar-07

Protein chains

O66950  (O66950_AQUAE) -  Twitching motility protein PilT from Aquifex aeolicus (strain VF5)

Seq: 366 a.a.

Struc: 343 a.a.

DOI no: 10.1016/j.str.2007.01.018

Structure 15:363-376 (2007)

PubMed id: 17355871

Crystal structures of the pilus retraction motor PilT suggest large domain movements and subunit cooperation drive motility.

K.A.Satyshur, G.A.Worzalla, L.S.Meyer, E.K.Heiniger, K.G.Aukema, A.M.Misic, K.T.Forest.

ABSTRACT

PilT is a hexameric ATPase required for bacterial type IV pilus retraction and surface motility. Crystal structures of ADP- and ATP-bound Aquifex aeolicus PilT at 2.8 and 3.2 A resolution show N-terminal PAS-like and C-terminal RecA-like ATPase domains followed by a set of short C-terminal helices. The hexamer is formed by extensive polar subunit interactions between the ATPase core of one monomer and the N-terminal domain of the next. An additional structure captures a nonsymmetric PilT hexamer in which approach of invariant arginines from two subunits to the bound nucleotide forms an enzymatically competent active site. A panel of pilT mutations highlights the importance of the arginines, the PAS-like domain, the polar subunit interface, and the C-terminal helices for retraction. We present a model for ATP binding leading to dramatic PilT domain motions, engagement of the arginine wire, and subunit communication in this hexameric motor. Our conclusions apply to the entire type II/IV secretion ATPase family.

Selected figure(s)

Figure 3.
Figure 3. Conserved Elements of PilT Fold
(A) The NTD of PilT (colored as in Figure 2A) resembles the well-known PAS domain (gray, represented by the circadian clock protein Period; Yildiz et al., 2005). Noncanonical PAS elements (PilT αA and loops within Period) are removed for clarity.
(B) The core ATPase subdomain of PilT (green) is readily superimposable upon RecA (Story and Steitz, 1992) (gray). In this view, the least-squares calculation is over P-loop residues only. Type II/IV secretion ATPase family motifs Walker A (blue), Asp box (lime green), Walker B (magenta), and His box (orange) neighbor the bound nucleotide.
(C) Isolated, magnified view of the four sequence motifs described in (B), with ATP and signature invariant residues Lys149, Glu176, Glu217, and His242 depicted (blue, green, magenta, and orange, respectively).

Figure 8.
Figure 8. Model for Concerted PilT Motions
(A) The quasi-two-fold symmetric C2 crystal structure has two peripheral wide-open subunits (B, E; blue), two central “active” subunits (C, F; orange), and two central “resting” subunits (A, D; green). Four CTD:CTD interfaces are engaged (double lines). The remaining two are disengaged (zig-zag). Subunit F is clamped around bound nucleotide.
(B) When ATP (red) binds in the E cleft, the two domains close around the ligand (short black arrows), causing the β5/β6 arginines to approach the ATP. Because of the extensive CTD[D]:NTD[E] interface, the motion of NTD[E] forces the swiveling of CTD[D](in particular the C-terminal helices) toward the periphery of the hexamer (long gray arrow). Consequently, the D arginine fingers approach the E active site (double lines). On the other side of CTD[D], the interface likewise rearranges, disengaging CTD[C] from the D active site (zig-zag).
(C) Subunit D is now poised as the most peripheral, wide-open subunit and ready to bind nucleotide; E is clamped around nucleotide and contributing to an engaged CTD:CTD interface on either side.

The above figures are reprinted from an Open Access publication published by Cell Press: Structure (2007, 15, 363-376) copyright 2007.

Figures were selected by an automated process.