Critical structural and functional roles for the N-terminal insertion sequence in surfactant protein B analogs
| Autor: | Zhengdong Wang, Chun-Ling Jung, Robert H. Notter, Alan J. Waring, Frans J. Walther, Andrew P. Clark, Piotr Ruchala, Larry M. Gordon, Wesley M. Smith, José M. Hernández-Juviel, Shantanu Sharma |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Male
Models Molecular Stereochemistry Protein Conformation Dimer Molecular Sequence Data lcsh:Medicine Peptide Rats Sprague-Dawley 03 medical and health sciences chemistry.chemical_compound 0302 clinical medicine Protein structure Pulmonary surfactant Respiratory Medicine/Respiratory Failure Spectroscopy Fourier Transform Infrared Animals Pulmonary surfactant-associated protein B Amino Acid Sequence lcsh:Science Peptide sequence 030304 developmental biology Gel electrophoresis chemistry.chemical_classification 0303 health sciences Multidisciplinary Pulmonary Surfactant-Associated Protein B Chemistry lcsh:R Protein superfamily Surface Plasmon Resonance Respiratory Medicine/Respiratory Pediatrics Rats Molecular Weight Biochemistry Electrophoresis Polyacrylamide Gel lcsh:Q Pediatrics and Child Health/Neonatology 030217 neurology & neurosurgery Research Article |
| Zdroj: | PLoS ONE, Vol 5, Iss 1, p e8672 (2010) PLoS ONE |
| ISSN: | 1932-6203 |
| Popis: | Background Surfactant protein B (SP-B; 79 residues) belongs to the saposin protein superfamily, and plays functional roles in lung surfactant. The disulfide cross-linked, N- and C-terminal domains of SP-B have been theoretically predicted to fold as charged, amphipathic helices, suggesting their participation in surfactant activities. Earlier structural studies with Mini-B, a disulfide-linked construct based on the N- and C-terminal regions of SP-B (i.e., approximately residues 8-25 and 63-78), confirmed that these neighboring domains are helical; moreover, Mini-B retains critical in vitro and in vivo surfactant functions of the native protein. Here, we perform similar analyses on a Super Mini-B construct that has native SP-B residues (1-7) attached to the N-terminus of Mini-B, to test whether the N-terminal sequence is also involved in surfactant activity. Methodology/results FTIR spectra of Mini-B and Super Mini-B in either lipids or lipid-mimics indicated that these peptides share similar conformations, with primary alpha-helix and secondary beta-sheet and loop-turns. Gel electrophoresis demonstrated that Super Mini-B was dimeric in SDS detergent-polyacrylamide, while Mini-B was monomeric. Surface plasmon resonance (SPR), predictive aggregation algorithms, and molecular dynamics (MD) and docking simulations further suggested a preliminary model for dimeric Super Mini-B, in which monomers self-associate to form a dimer peptide with a "saposin-like" fold. Similar to native SP-B, both Mini-B and Super Mini-B exhibit in vitro activity with spread films showing near-zero minimum surface tension during cycling using captive bubble surfactometry. In vivo, Super Mini-B demonstrates oxygenation and dynamic compliance that are greater than Mini-B and compare favorably to full-length SP-B. Conclusion Super Mini-B shows enhanced surfactant activity, probably due to the self-assembly of monomer peptide into dimer Super Mini-B that mimics the functions and putative structure of native SP-B. |
| Databáze: | OpenAIRE |
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