1SSZ

Conformational Mapping of Mini-B: An N-terminal/C-terminal Construct of Surfactant Protein B Using 13C-Enhanced Fourier Transform Infrared (FTIR) Spectroscopy

Summary for 1SSZ

• Entry DOI: 10.2210/pdb1ssz/pdb
• Descriptor: Pulmonary surfactant-associated protein B (1 entity in total)
• Functional Keywords: lung surfactant protein, saposin, surface active protein
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 3934.02

Authors

Waring, A.J.,Walther, F.J.,Gordon, L.M.,Hernandez-Juviel, J.M.,Hong, T.,Sherman, M.A.,Alonso, C.,Alig, T.,Braun, A.,Bacon, D.,Zasadzinski, J.A. (deposition date: 2004-03-24, release date: 2004-06-15, Last modification date: 2024-10-30)

Primary citation

Waring, A.J.,Walther, F.J.,Gordon, L.M.,Hernandez-Juviel, J.M.,Hong, T.,Sherman, M.A.,Alonso, C.,Alig, T.,Braun, A.,Bacon, D.,Zasadzinski, J.A.
The role of charged amphipathic helices in the structure and function of surfactant protein B.
J.Pept.Res., 66:364-374, 2005

PubMed Abstract: Surfactant protein B (SP-B) is essential for normal lung surfactant function. Theoretical models predict that the disulfide cross-linked, N- and C-terminal domains of SP-B fold as charged amphipathic helices, and suggest that these adjacent helices participate in critical surfactant activities. This hypothesis is tested using a disulfide-linked construct (Mini-B) based on the primary sequences of the N- and C-terminal domains. Consistent with theoretical predictions of the full-length protein, both isotope-enhanced Fourier transform infrared (FTIR) spectroscopy and molecular modeling confirm the presence of charged amphipathic alpha-helices in Mini-B. Similar to that observed with native SP-B, Mini-B in model surfactant lipid mixtures exhibits marked in vitro activity, with spread films showing near-zero minimum surface tensions during cycling using captive bubble surfactometry. In vivo, Mini-B shows oxygenation and dynamic compliance that compare favorably with that of full-length SP-B. Mini-B variants (i.e. reduced disulfides or cationic residues replaced by uncharged residues) or Mini-B fragments (i.e. unlinked N- and C-terminal domains) produced greatly attenuated in vivo and in vitro surfactant properties. Hence, the combination of structure and charge for the amphipathic alpha-helical N- and C-terminal domains are key to SP-B function.

PubMed: 16316452
DOI: 10.1111/j.1399-3011.2005.00300.x

Experimental method

INFRARED SPECTROSCOPY