Xudong Yao

Analytical Chemistry and Proteomics

Assistant Professor (b. 1965)

Scientist II, Millennium Pharmaceuticals, 2002-2004

Senior Scientist, GeneProt, 2002
Postdoctoral Associate, University of Maryland, 1999-2002
Ph.D., University of Maryland Baltimore County, 2000
M.S., Nanjing University, 1987

B.S., Nanjing University, 1984

Phone: 860-486-6644
Email : x.yao@uconn.edu

Yao Group Home Page

Research

We invent and develop novel technologies to meet analytical challenges in complex and dynamic “-ome” samples, with an emphasis on analysis of phosphorylated molecules.

Labeling of Phosphates on Biomolecules

We have demonstrated for the first time that chemical mediation can label pre-existing phosphate with stable oxygen isotopes. This labeling causes minimal structural changes of peptidyl phosphates and allows the direct translation of modification-specific mass spectrometry that has been established for phosphopeptide and phosphoproteome analysis.

Sequence-Independent Quantitation of Phosphotyrosinyl Peptides

Phosphotyrosinyl peptides generate the immonium ion of phosphotyrosine residue, via collision-induced dissociation in gas phase. Differential oxygen labels on the phosphates result in ¹⁶O/¹⁸O immonium ions. Their intensities can be used for relative quantitation, without the need of isotope deconvolution of individual phosphopeptides that have different amino acid sequences. In conjunction with parallel fragmentation mass spectrometry, a mass spectrometric method promoted by us among several other groups, we are developing methods that use oxygen-labeled phosphotyrosine immonium ions for analysis of phosphoproteomes.

Recent Publications:

1. Y. Shi, X. Yao “Oxygen isotopic substitution of peptidyl phosphates for modification-specific mass spectrometry,” Analytical Chemistry, 2007, 79, 8454.

2. A.A. Ramos, H. Yang, L.E. Rosen, and X. Yao “Tandem Parallel Fragmentation of Peptides for Mass Spectrometry,” Analytical Chemistry, 2006, 78, 6391.

3. M. Heller, H. Mattou, C. Menzel, X. Yao “Trypsin catalyzed ¹⁶O-to-¹⁸O exchange for comparative proteomics: comparison on tandem mass spectrometry using MALDI-TOF, ESI-QqTOF and ESI-ion trap mass spectrometers,” Journal of American Society for Mass Spectrometry, 2003, 14, 704.

4. X. Yao, C. Afonso, C. Fenselau “Dissection of proteolytic ¹⁸O labeling: endoprotease-catalyzed ¹⁶O-to-¹⁸O exchange of truncated peptide substrates,” Journal of Proteome Research, 2003, 2, 147.

5. K. Shefcheck, X. Yao, C. Fenselau “Fractionation of cytosolic proteins on an immobilized heparin column,” Analytical Chemistry, 2003, 75, 1691.

6. K. J. Reynolds, X. Yao, C. Fenselau “Proteolytic ¹⁸O labeling for comparative proteomics: evaluation of endoprotease Glu-C as the catalytic agent,” Journal of Proteome Research, 2002, 1, 28.

7. X. Yao, A. Freas, J. Ramirez, P.A. Demirev, C Fenselau “Proteolytic ¹⁸O labeling for comparative proteomics: model studies with two serotypes of adenovirus,” Analytical Chemistry, 2001, 73, 2836.

8. X. Yao, M.A. Gold, R. M. Pollack “Transition state imbalance in proton transfer from phenyl ring substituted 2-tetralones to acetate ion,” Journal of the American Chemical Society, 1999, 121, 6220.