LabAutomation 2006 - SLAS

Where Laboratory Technologies Emerge and Merge
11:00 am Tuesday, January 24, 2006 Track 1: Detection & Separation Room: Catalina
Wyndham Palm Springs Hotel
Anders Nordstrom
Co-Author(s)
The Scripps Research Institute
Gary Siuzdak
San Diego, California
andersn@scripps.edu
The Scripps Research Institute Center for Mass Spectrometry
Enhancing Desorption/Ionization on Silicon Mass Spectrometry (DIOS-MS)
Desorption/Ionization on Silicon (DIOS) is a versatile platform for protein identification and characterization as well as small molecule
analysis. The DIOS technique offers high tolerance towards salts, buffers and complicated matrices. Moreover, the DIOS surface can be
tailored to selective capture and enrich particular species and in this manner provide a means of both sample preparation and analysis.
Recent experiments illustrate that perfluorinated DIOS surfaces can be doped with perfluorinated surfactants (carboxylic and sulfonic acids)
to further enhance its mass analysis capabilities. This stands in contrast to the general view that surfactants are suppressing agents when
combined with mass spectrometry. The implications for characterizing the desorption/ionization mechanism, the use of surfactants and the
prospects of further improvement of DIOS utility will be addressed
11:30 am Tuesday, January 24, 2006 Track 1: Detection & Separation Room: Catalina
Wyndham Palm Springs Hotel
Rachel Loo
Co-Author(s)
University of California-Los Angeles
Yanan Yang
Los Angeles, California
Pinmanee Boontheung
rloo@mednet.ucla.edu
Joseph Loo
Top-Down, Bottom-Up, and Side-to-Side Proteomics With Virtual 2D Gels
Bottom-up proteomics strategies identify proteins in complex mixtures, but discard most information revealing protein isoforms,
modifications, and unanticipated processing. Top-down proteomics strategies retain much of this information when providing both
accurate intact mass and sequence data, but rely on compatible protein separation technologies lacking the resolution, broad applicability,
and interlaboratory reproducibility of gel-based methods. Combining top-down and bottom-up assets, “Virtual 2D gel electrophoresis”
links isoform-specific measurements accessed by 2D gels (e.g., antibody binding, carbohydrate composition, synthesis/degradation rate,
abundance, enzymatic activity) to unambiguous identifications.
Long a challenge for mass spectrometry, measurements of polyacrylamide gel-isolated intact proteins are acquired by Virtual 2D Gel
Electrophoresis, by directly mass-analyzing dried isoelectric focusing (IEF) gels. Essentially, MALDI-MS replaces the SDS-PAGE 2nd
dimension of classical 2D Polyacrylamide Gel Electrophoresis (PAGE), producing data for direct comparison to stained classical 2D
gels. Once linked to individual 2D spots, mass measurements achieve enduring utility, relevant to every subsequent and previous 2D gel
analysis, dramatically reducing proteomic workloads and increasing the probability that data will further knowledge. Our examination of high
density lipoproteins (HDL) suggested annotations for 20 year-old 2D gels and exposed previously unknown glycosylation.
MALDI-MS determined intact masses are linked to unambiguous protein identities by:
Top-Down: MALDI In-Source Dissociation
Bottom-Up: Tryptic Digest and MALDI-MS/MS from IEF Gel
Side-to-Side: MALDI-MS from IEF. Identify from correspondence to known spot on classical 2D PAGE.
Applications to < 3 to 100 kDa proteins in microbial and mammalian cell cultures, human HDL, and small, precious tissue samples will be
discussed.
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