Improvement of protein identification performance by reinterpreting the precursor ion mass tolerance of mass spectrum

질량스펙트럼의 펩타이드 분자량 오차범위 재해석에 의한 단백질 동정의 성능 향상

  • 권경훈 (한국기초과학지원연구원 연구장비개발부) ;
  • 김진영 (한국기초과학지원연구원 단백질체구조연구부) ;
  • 박건욱 (한국기초과학지원연구원 연구장비개발부) ;
  • 이정화 (한국기초과학지원연구원 단백질체구조연구부) ;
  • 백융기 (연세프로테옴연구센터, 질병유전단백체연구지원센터) ;
  • 유종신 (한국기초과학지원연구원 연구장비개발부)
  • Published : 2006.05.28

Abstract

In proteomics research, proteins are digested into peptides by an enzyme and in mass spectrometer, these peptides break into fragment ions to generate tandem mass spectra. The tandem mass spectral data obtained from the mass spectrometer consists of the molecular weights of the precursor ion and fragment ions. The precursor ion mass of tandem mass spectrum is the first value that is fetched to sort the candidate peptides in the database search. We look far the peptide sequences whose molecular weight matches with precursor ion mass of the mass spectrum. Then, we choose one peptide sequence that shows the best match with fragment ions information. The precursor ion mass of the tandem mass spectrum is compared with that of the digested peptides of protein database within the mass tolerance that is assigned by users according to the mass spectrometer accuracy. In this study, we used reversed sequence database method to analyze the molecular weight distribution of precursor ions of the tandem mass spectra obtained by the FT LTQ mass spectrometer for human plasma sample. By reinterpreting the precursor ion mass distribution, we could compute the experimental accuracy and we suggested a method to improve the protein identification performance.