engleski

Sequencing of peptides/proteins and organisms ID

The organism identification tests are used to characterize microorganisms in human body, environmental samples(microorganisms and organisms)or simply to identify organisms of interest (e.g.what we have had forlunch?). Currently used techniques for species identication are mostly relied on genome database matching (limited to 20000 species)commercially available protein database matching (limited to 3000 species)or alternatively on immunological procedures (limited to a couple of hundreds species). Although widely used, such an approach does not always provide satisfactory matching, sequence coverage or specific antigen-antibody reaction to unambiguously identify DNA, RNA, lipid, and sugar or peptide/protein of selected species. Mass spectrometry as a tool for species determination was introduced about ten years ago. Matrix assisted laser desorptionion izationtime of flight mass spectrometry (MALDI-TOFMS) identifies microbes using either intact cells or cell extracts.The most abunded proteins from the cell detected in the instrument are matched against commercially available databases that cover relatively limited number of microbes. On the other hand, high resolution mass spectrometers in contrast to MALDI-TOF MS could provide more accurate and precise results after de novo sequencing of analyzed proteins.A brief historical retrospective, as well as state-of-the-art methodology of species identication will be covered in the lecture.

Species ID ; peptide/protein sequencing

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