title: Determination of disulfide bond patterns in laminin beta1 chain N-terminal domains by nano-high-performance liquid chromatography/matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry.
abstract: The disulfide bonding patterns in the N-terminal (LN) domains of the basement membrane protein laminin beta1 have not been investigated so far. We report an in-depth mass spectrometric analysis using offline nano-high-performance liquid chromatography/matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (nano-HPLC/MALDI-TOF/TOF-MS) for determining the disulfide bond patterns in the LN-domain of recombinant mouse laminin beta1 chain for the first time. Mass spectra were recorded and the putatively disulfide-linked peptides were subjected to LIFT-TOF/TOF-MS to confirm the disulfide bond. Screening the fragment ion mass spectra of disulfide-linked peptides for characteristic 66-amu patterns (34 u +32 u), arising from symmetric and asymmetric cleavage of disulfide bonds, facilitated their identification. Using various enzymes for proteolytic digestion of a recombinant laminin beta1 chain N-terminal protein fragment, a linear bonding pattern of the eight cysteine residues in the LN-domain of the laminin beta1 chain was observed with a (1-2, 3-4, 5-6, 7-8) connectivity of cysteines. The identical disulfide-bonding pattern was found in E4, the N-terminal laminin beta1 chain fragment derived by elastase digestion of mouse tumor laminin-111, confirming that this pattern also occurs in native laminin.
authors.affiliation: Department of Pharmaceutical Chemistry & Bioanalytics, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, D-06120 Halle, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Kalkhof
authors.forename: Sebastian
authors.initials: S
authors.lastname: Haehn
authors.forename: Christian
authors.initials: C
authors.lastname: Ihling
authors.forename: Mats
authors.initials: M
authors.lastname: Paulsson
authors.forename: Neil
authors.initials: N
authors.lastname: Smyth
authors.forename: Andrea
authors.initials: A
authors.lastname: Sinz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004220:Disulfides / Q000032:analysis / Q000737:chemistry*; D006801:Humans; D007668:Kidney / Q000166:cytology; D007797:Laminin / Q000737:chemistry* / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D036103:Nanotechnology; D010449:Peptide Mapping; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D004220:Disulfides; D007797:Laminin; D011994:Recombinant Proteins