title: Strain-based sequence variations and structure analysis of murine prostate specific spermine binding protein using mass spectrometry.
abstract: Mouse spermine binding protein (SBP) has been characterized using mass spectrometry, including its localization within the prostate, sequence verification, and its posttranslational modifications. MALDI (matrix-assisted laser desorption/ionization) mass spectrometry was employed for localization of proteins expressed by different lobes of the mouse prostate obtained after tissue blotting on a polyethylene membrane. The mass spectra showed complex protein profiles that were different for each lobe of the prostate. The prostate-specific spermine binding protein (SBP), primarily identified by its in-source decay fragment ion signals, was found predominantly expressed by the ventral lobe of the prostate. The MALDI in-source decay measurements combined with nanoESI (nanoelectrospay ionization) MS/MS measurements obtained after specific proteolysis of SBP, allowed the exact positioning of a single N-linked carbohydrate group, and the identification of a pyroglutamate residue at the sequence N-terminus. The N-linked carbohydrate component was further investigated and the general pattern of the N-linked carbohydrate identified. The presence of a disulfide bridge between cysteine78 and cysteine124 was also established. The full sequence characterization of SBP showed several strain-based sequence differences when compared to the published gene sequence.
authors.affiliation: Department of Biochemistry, Vanderbilt University, Nashville, Tennessee 37232-6400, USA.
authors.forename: P
authors.initials: P
authors.lastname: Chaurand
authors.forename: B B
authors.initials: BB
authors.lastname: DaGue
authors.forename: S
authors.initials: S
authors.lastname: Ma
authors.forename: S
authors.initials: S
authors.lastname: Kasper
authors.forename: R M
authors.initials: RM
authors.lastname: Caprioli
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry* / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism; D011467:Prostate / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014020:Tissue Extracts / Q000737:chemistry
chemical_list: D002352:Carrier Proteins; D010455:Peptides; D014020:Tissue Extracts