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Event Type:  Lecture (This is an NIH Science event)
Title:  Site-specific Glycopeptide Identification by Tandem Mass Spectrometry
Description:  Abstract: The characterization of intact glycopeptides by tandem mass spectrometry has significant potential for elucidating site-specific glycosylation of proteins, providing insight into perturbed disease, tissue, subcellular location, and other context dependent glycosylation pathways. However, there are substantial informatics challenges that must be solved to meet this promise. The GlycoPeptideSearch (GPS) tool, developed for CID tandem mass spectra of intact glycopeptides, uses a novel decoy strategy to estimate glycopeptide false discovery rates, and seeks to characterize distinct glycan structures on peptide substrates, not just monosaccharide composition. Importantly, the focus on glycan structures requires careful handling of glycopeptides that may or may not be readily distinguishable by tandem mass spectrometry, and has led to work on describing the relationships between partially described or characterized glycan structures. We are currently extending GPS to take advantage of advanced mass-spectrometry fragmentation techniques, such as HCD triggered ETD (HCDpdETD), combined ETD/HCD fragmentation (EThcD), and multi-collision energy spectra. In each case, these multi-spectra observations from the same precursor ion require new informatics strategies, and, in particular, new FDR estimation techniques. We have implemented a lattice-based multi-metric FDR estimation technique suitable for multi-spectra, multi-fragmentation mode workflows that demonstrates significant improvement over fixed filtering approaches. Lastly, we apply precursor mass-delta tolerant spectral matching to build spectral networks of glycopeptide tandem mass-spectra so that high confidence glycopeptide identifications can be used to make glycopeptide assignments to related spectra. We hope that together, these
strategies will soon make glycopeptide identification by tandem mass spectrometry as routine and informative as peptide identification from bottom-up proteomics workflows.
Series Name:  Proteomics Interest Group Lecture Series
Videocast:  Event will be videocast LIVE on the Web
Videocast URL:
  Event will be available in the videocast ARCHIVE
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Thursday, November 02, 2017   9:30am - 10:30am Add To Outlook Calendar     Add To iCal Calendar     Add To Entourage Calendar
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Name:   Nathan Edwards
Title:   Ph. D.
Organization:   Georgetown University
City/Province:   Washington
State:   District of Columbia
Country:   USA

Organization(s):  Proteomics Interest Group

Location:  On the main NIH Campus
Building:  50
Room:  1328/1334
Street Address:  9000 Rockville Pike
City:  Bethesda
State:  Maryland
Zip Code:  20892

Name:   Aleksandra Nita-Lazar
Phone:   301-451-4394
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