Recombinant human SP-A1 and SP-A2 proteins have different carbohydrate-binding characteristics

Rebecca E. Oberley, Jeanne M. Snyder

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Surfactant protein (SP)-A is a member of the collectin family of proteins and plays a role in innate host defense of the lung. SP-A binds to the carbohydrates of lung pathogens via its calcium-dependant carbohydrate-binding domain. Native human alveolar SP-A consists of two distinct gene products: SP-A1 and SP-A2; however, only SP-A2 is expressed in the submucosal glands of the conducting airways. The function of the isolated SP-A2 protein is unknown. We hypothesized that SP-A1 and SP-A2 might have different carbohydrate-binding properties. In this study, we characterized the carbohydrate-binding specificities of native human alveolar SP-A and recombinant human SP-A1 and SP-A2 in the presence of either 1 or 5 mM Ca2+. We found that all of the SP-A proteins bind carbohydrates but with different affinities. All of the SP-A proteins bind to fucose with the greatest affinity, SP-A2 binds with a higher affinity to a wider variety of sugars than SP-A1 at either 1 or 5 mM Ca2+. These findings are suggestive that SP-A2 may interact with a greater variety of pathogens than native SP-A.

Original languageEnglish (US)
Pages (from-to)L871-L881
JournalAmerican Journal of Physiology - Lung Cellular and Molecular Physiology
Issue number5 28-5
StatePublished - May 1 2003
Externally publishedYes


  • Innate host defense
  • Lung
  • Surfactant
  • Surfactant protein A

ASJC Scopus subject areas

  • Physiology
  • Pulmonary and Respiratory Medicine
  • Physiology (medical)
  • Cell Biology


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