Strain-based sequence variations and structure analysis of murine prostate specific spermine binding protein using mass spectrometry

Biochemistry. 2001 Aug 14;40(32):9725-33. doi: 10.1021/bi010424l.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Carrier Proteins / chemistry*
  • Carrier Proteins / metabolism
  • Chromatography, High Pressure Liquid
  • Male
  • Mice
  • Molecular Sequence Data
  • Peptides / metabolism
  • Prostate / chemistry*
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
  • Tissue Extracts / chemistry


  • Carrier Proteins
  • Peptides
  • Tissue Extracts