PDBsum entry 2odl

Cell adhesion

PDB id: 2odl

Contents

Protein chain

372 a.a. *

Waters ×182

* Residue conservation analysis

PDB id:

2odl

Name:

Cell adhesion

Title:

Crystal structure of the hmw1 secretion domain from haemophilus influenzae

Structure:

Adhesin. Chain: a. Fragment: residues 69-441. Engineered: yes

Source:

Haemophilus influenzae. Organism_taxid: 727. Strain: 12. Gene: hmw1a. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Resolution:

1.92Å R-factor: 0.176 R-free: 0.217

Authors:

T.Yokoyama,H.J.Yeo

Key ref:

H.J.Yeo et al. (2007). The structure of the Haemophilus influenzae HMW1 pro-piece reveals a structural domain essential for bacterial two-partner secretion. J Biol Chem, 282, 31076-31084. PubMed id: 17699157 DOI: 10.1074/jbc.M705750200

Date:

22-Dec-06 Release date: 21-Aug-07

Protein chain

Q48031  (Q48031_HAEIF) -  Adhesin from Haemophilus influenzae

Seq: 1536 a.a.

Struc: 372 a.a.

DOI no: 10.1074/jbc.M705750200

J Biol Chem 282:31076-31084 (2007)

PubMed id: 17699157

The structure of the Haemophilus influenzae HMW1 pro-piece reveals a structural domain essential for bacterial two-partner secretion.

H.J.Yeo, T.Yokoyama, K.Walkiewicz, Y.Kim, S.Grass, J.W.Geme.

ABSTRACT

In pathogenic Gram-negative bacteria, many virulence factors are secreted via the two-partner secretion pathway, which consists of an exoprotein called TpsA and a cognate outer membrane translocator called TpsB. The HMW1 and HMW2 adhesins are major virulence factors in nontypeable Haemophilus influenzae and are prototype two-partner secretion pathway exoproteins. A key step in the delivery of HMW1 and HMW2 to the bacterial surface involves targeting to the HMW1B and HMW2B outer membrane translocators by an N-terminal region called the secretion domain. Here we present the crystal structure at 1.92 A of the HMW1 pro-piece (HMW1-PP), a region that contains the HMW1 secretion domain and is cleaved and released during HMW1 secretion. Structural analysis of HMW1-PP revealed a right-handed beta-helix fold containing 12 complete parallel coils and one large extra-helical domain. Comparison of HMW1-PP and the Bordetella pertussis FHA secretion domain (Fha30) reveals limited amino acid homology but shared structural features, suggesting that diverse TpsA proteins have a common structural domain required for targeting to cognate TpsB proteins. Further comparison of HMW1-PP and Fha30 structures may provide insights into the keen specificity of TpsA-TpsB interactions.

Selected figure(s)

Figure 1.
FIGURE 1. Domain organization of HMW1 and model for TPS. The HMW1 signal sequence (residues 1-68) is shown in yellow, the HMW1 pro-piece (residues 69-441) is shown in magenta, and the mature HMW1 adhesin (442-1536) is shown in blue (a large cell surface structure) and in orange (a small C-terminal anchor). For clarity, only the secretion process across the outer membrane is presented. After Sec-dependent export of the HMW1 preproprotein across the inner membrane, the HMW1 secretion domain interacts with HMW1B, likely in the periplasm, facilitating translocation of HMW1 across the outer membrane. Sometime during this translocation process, HMW1-PP is cleaved and released to the extracellular space (S. Grass and J. W. St. Geme III, unpublished data). Ultimately, the binding domain of mature HMW1 is exposed on the tip of the adhesin, away from the bacterial cell surface, in a position that favors access to host cells.

Figure 3.
FIGURE 3. Electrostatic potential surface of HMW1-PP using GRASP (39). Positive and negative potentials are indicated in blue and red, respectively. The major pocket formed on the PB2 face is indicated.

The above figures are reprinted by permission from the ASBMB: J Biol Chem (2007, 282, 31076-31084) copyright 2007.

Figures were selected by an automated process.