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Location of Structural Transitions in an Isotopically Labeled Lung Surfactant SP-B Peptide by IRRAS
- Source :
- Biophysical Journal. 85:340-349
- Publication Year :
- 2003
- Publisher :
- Elsevier BV, 2003.
-
Abstract
- Pulmonary surfactant, a lipid/protein complex that lines the air/water interface in the mammalian lung, functions to reduce the work of breathing. Surfactant protein B (SP-B) is a small, hydrophobic protein that is an essential component of this mixture. Structure-function relationships of SP-B are currently under investigation as the protein and its peptide analogs are being incorporated into surfactant replacement therapies. Knowledge of the structure of SP-B and its related peptides in bulk and monolayer phases will facilitate the design of later generation therapeutic agents. Prior infrared reflection-absorption spectroscopic studies reported notable, reversible surface pressure-induced antiparallel beta-sheet formation in a synthetic peptide derived from human SP-B, residues 9-36 (SP-B(9-36)). In the current work, infrared reflection-absorption spectroscopy is applied in conjunction with isotopic labeling to detect the site and pressure dependence of the conformational change. SP-B(9-36), synthesized with (13)C=O-labeled Ala residues in positions 26, 28, 30, and 32, shifted the beta-sheet marker band to approximately 1600 cm(-1) and thus immediately identified this structural element within the labeled region. Surface pressure-induced alterations in the relative intensities of Amide I band constituents are interpreted using a semiempirical transition dipole coupling model. In addition, electron micrographs reveal the formation of tubular myelin structures from in vitro preparations using SP-B(9-36) in place of porcine SP-B indicating that the peptide has the potential to mimic this property of the native protein.
- Subjects :
- Models, Molecular
Conformational change
Spectrophotometry, Infrared
Protein Conformation
Molecular Sequence Data
Biophysics
Peptide
010402 general chemistry
01 natural sciences
Phase Transition
Isotopic labeling
Structure-Activity Relationship
03 medical and health sciences
Protein structure
Species Specificity
Pulmonary surfactant
Monolayer
Animals
Humans
Surface Tension
Organic chemistry
Computer Simulation
Pulmonary surfactant-associated protein B
Amino Acid Sequence
Peptide sequence
Myelin Sheath
030304 developmental biology
chemistry.chemical_classification
Biological Products
0303 health sciences
Membranes
Crystallography
Pulmonary Surfactant-Associated Protein B
Chemistry
Proteins
Pulmonary Surfactants
Rats
0104 chemical sciences
Isotope Labeling
Swine, Miniature
Subjects
Details
- ISSN :
- 00063495
- Volume :
- 85
- Database :
- OpenAIRE
- Journal :
- Biophysical Journal
- Accession number :
- edsair.doi.dedup.....a585ffaf6ed3c1634fef5fe5a54732d6