Carbohydrate recognition and neck domains of surfactant protein A (SP-A)

Experimental Data Snapshot

  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.221 

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Crystal structure of trimeric carbohydrate recognition and neck domains of surfactant protein A

Head, J.F.Mealy, T.R.McCormack, F.X.Seaton, B.A.

(2003) J Biol Chem 278: 43254-43260

  • DOI: https://doi.org/10.1074/jbc.M305628200
  • Primary Citation of Related Structures:  
    1R13, 1R14

  • PubMed Abstract: 

    Surfactant protein A (SP-A), one of four proteins associated with pulmonary surfactant, binds with high affinity to alveolar phospholipid membranes, positioning the protein at the first line of defense against inhaled pathogens. SP-A exhibits both calcium-dependent carbohydrate binding, a characteristic of the collectin family, and specific interactions with lipid membrane components. The crystal structure of the trimeric carbohydrate recognition domain and neck domain of SP-A was solved to 2.1-A resolution with multiwavelength anomalous dispersion phasing from samarium. Two metal binding sites were identified, one in the highly conserved lectin site and the other 8.5 A away. The interdomain carbohydrate recognition domain-neck angle is significantly less in SP-A than in the homologous collectins, surfactant protein D, and mannose-binding protein. This conformational difference may endow the SP-A trimer with a more extensive hydrophobic surface capable of binding lipophilic membrane components. The appearance of this surface suggests a putative binding region for membrane-derived SP-A ligands such as phosphatidylcholine and lipid A, the endotoxic lipid component of bacterial lipopolysaccharide that mediates the potentially lethal effects of Gram-negative bacterial infection.

  • Organizational Affiliation

    Department of Physiology and Biophysics, Boston University School of Medicine, Boston, Massachusetts 02118, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Pulmonary surfactant-associated protein A148Rattus norvegicusMutation(s): 1 
Find proteins for P08427 (Rattus norvegicus)
Explore P08427 
Go to UniProtKB:  P08427
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP08427
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.10 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.221 
  • R-Value Observed: 0.221 
  • Space Group: P 63
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 97.68α = 90
b = 97.68β = 90
c = 44.54γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-11-18
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references, Derived calculations