Crystal structure of the HMW1 secretion domain from Haemophilus influenzae

Experimental Data Snapshot

  • Resolution: 1.92 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 

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

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

(2007) J Biol Chem 282: 31076-31084

  • DOI: https://doi.org/10.1074/jbc.M705750200
  • Primary Citation of Related Structures:  

  • PubMed 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.

  • Organizational Affiliation

    Department of Biology and Biochemistry, University of Houston, Houston, Texas 77204, USA. hyeo@uh.edu

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Adhesin373Haemophilus influenzaeMutation(s): 4 
Gene Names: hmw1A
Find proteins for Q48031 (Haemophilus influenzae)
Explore Q48031 
Go to UniProtKB:  Q48031
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ48031
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on MSE
Experimental Data & Validation

Experimental Data

  • Resolution: 1.92 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.174 
  • R-Value Observed: 0.176 
  • Space Group: I 4
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 121.438α = 90
b = 121.438β = 90
c = 50.582γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-08-21
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-12-27
    Changes: Data collection, Database references, Derived calculations