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Peptide‐binding specificity of the prosurfactant protein C Brichos domain analyzed by electrospray ionization mass spectrometry
Author(s) -
Fitzen Michael,
Alvelius Gunvor,
Nordling Kerstin,
Jörnvall Hans,
Bergman Tomas,
Johansson Jan
Publication year - 2009
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.4282
Subject(s) - chemistry , electrospray ionization , peptide , mass spectrometry , tandem mass spectrometry , protein mass spectrometry , electrospray , biophysics , biochemistry , chromatography , biology
The C‐terminal domain of lung surfactant protein C (CTC) precursor (proSP‐C) is involved in folding of the transmembrane segment of proSP‐C. CTC includes a Brichos domain with homologs in cancer‐ and dementia‐associated proteins. Mutations in the Brichos domain cause misfolding of proSP‐C and hence amyloid fibril formation in interstitial lung disease. Electrospray ionization mass spectrometry (ESI‐MS) with collision‐induced dissociation (CID) experiments was applied to study non‐covalent interactions between human recombinant CTC or its Brichos domain, and SP‐C analogs, homotripeptides and peptides designed to model amyloid fibril formation. The results show that the Brichos domain contains the peptide‐binding function of CTC. In titration experiments, apparent dissociation constants (K D ) were in the micromolar range where triple‐valine showed the lowest K D and triple‐tyrosine the highest. Non‐hydrophobic peptides failed to form complexes with Brichos. CID revealed that complexes with aromatic peptide ligands are more stable in the gas phase than complexes with non‐aromatic ligands. The Brichos domain was also shown to bind fibril‐forming peptides containing aromatic/hydrophobic residues. Copyright © 2009 John Wiley & Sons, Ltd.