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Joseph A. Loo

Professor of Chemistry and Biochemistry

BS, Chemistry, Clarkson University; MS and PhD, Analytical Chemistry, Cornell University; Postdoctoral fellow, Pacific Northwest National Laboratory; Member of UCLA Molecular Biology Institute and UCLA-DOE Institute for Genomics and Proteomics

Current Research     |      Representative Publications  
Phone: (310) 794-7023
Fax: (310) 206-4038

UCLA Department of Chemistry & Biochemistry
402 Paul Boyer Hall (MBI)

Box 951569 (post)
607 Charles E. Young Drive East (courier)
Los Angeles, CA 90095-1569

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 Current Research Interests

The research interests of Professor Loo’s group include the development and application of bioanalytical methods for the structural characterization of proteins and post-translational modifications, proteomics-based research, and the elucidation of protein biomarkers of disease. Mass spectrometry and protein separation methods are central tools for the lab. The composition and structure of noncovalently-bound protein-protein and protein-ligand interactions are studied by electrospray ionization mass spectrometry and ion mobility.

 Representative Publications

Loo ­JA, Edmonds­ CG, and Smith­ RD. “Primary Sequence Information from Intact Proteins by Electrospray Ionization Tandem Mass Spectrometry.” Science 1990;248:201-204.

Loo JA. “Studying Noncovalent Protein Complexes by Electrospray Ionization Mass Spectrometry.” Mass Spectrom Rev 1997;16:1-23.

Loo, JA. “Electrospray Ionization Mass Spectrometry: A Technology for Studying Noncovalent Macromolecular Complexes.” Int J Mass Spectrom 2000; 200:175-186.

Thevis M, Ogorzalek Loo RR, and Loo JA. “In-Gel Derivatization of Proteins for Cysteine-Specific Cleavages and their Analysis by Mass Spectrometry.” J Proteome Res 2003; 2: 163-172.

Thevis M, Ogorzalek Loo RR, and Loo JA. “Mass Spectrometric Characterization of Transferrins and their Fragments Derived by Reduction of Disulfide Bonds.” J Am Soc Mass Spectrom 2003; 14: 635-647.

Daoud Kinzie S, Thevis M, Ngo K, Whitelegge J, Loo JA, and Abu-Omar MM. “Posttranslational hydroxylation of human phenylalanine hydroxylase is a novel example of enzyme self-repair within the second coordination sphere of catalytic iron.” J Am Chem Soc 2003; 125: 4710-4711.

Nitao LK, Ogorzalek Loo RR, O’Neall-Hennessey E, Loo JA, Szent-Györgyi AG, and Reisler E. “Conformation and Dynamics of the SH1-SH2 Helix in Scallop Myosin.” Biochemistry 2003; 42: 7663-7674.

Thevis M, Ogorzalek Loo RR, Loo JA, and Schänzer W. “Doping Control Analysis of Bovine Hemoglobin-Based Oxygen Therapeutics in Human Plasma by LC-Electrospray Ionization-MS/MS.” Anal Chem 2003; 75: 3287-3293.

Xiao GG, Wang M, Macatangay G, Li N, Loo JA, and Nel AE. “Use of Proteomics to Demonstrate a Hierarchical Oxidative Stress Response to Diesel Exhaust Particles in a Macrophage Cell Line.” J Biol Chem 2003; 278: 50781-50790.

Alfonta L, Zhang Z, Uryu S, Loo JA, and Schultz PG. “Site-Specific Incorporation of a Redox-Active Amino Acid into Proteins.” J Am Chem Soc 2003; 125: 14662-14663.

Xian M, Fatima Z, Zhang W, Fang J, Li H, Pei D, Loo J, Stevenson T, Wang GP. “Identification of α-Galactosyl Epitope Mimetics through Rapid Generation and Screening of C-Linked Glycopeptide Library.” J Combinatorial Chem 2004; 6: 126-134.

Zhang Z, Gildersleeve J,Yang Y-Y, Xu R, Loo JA, Uryu S, Wong C-H, Schultz PG. "A New Strategy for the Synthesis of Glycoproteins.” Science 2004; 303: 371-373.

Wheeler AR, Moon H, Kim C-J, Loo JA, Garrell RL. “Digital Microfluidics for Analysis of Peptides and Proteins by Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS).” Anal Chem 2004; 76: 4833-4838.

Ogorzalek Loo RR, Lam Y, Loo JA, and Schumaker VN. “Virtual 2-D Gel Electrophoresis of High Density Lipoproteins.” Electrophoresis 2004; 25: 2384-2391.

Dyall SD, Yan W, Delgadillo-Correa MG, Lunceford A, Loo JA, Clarke CF, and Johnson PJ. “Complex I proteins of non-mitochondrial origin in a Trichomonas hydrogenosomal oxidoreductase complex.” Nature 2004; 431: 1103-1107.

Guo S, Ferl GZ, Deora R, Riedinger M, Yin S, Kerwin JL, Loo JA, and Witte ON. “A phosphorylation site in Bruton's tyrosine kinase selectively regulates B cell calcium signaling efficiency by altering phospholipase C-γ activation” Proc Natl Acad Sci USA 2004; 101: 14180-14185.

Hu S, Denny P, Denny P, Xie Y, Loo JA, Wolinsky LE, Li Y, McBride J, Ogorzalek Loo RR, Navazesh M, and Wong DT. “Differentially Expressed Proteins Markers in Human Submandibular and Sublingular Secretions.” Int J Oncology 2004; 25: 1423-1430.

Wheeler AR, Moon H, Kim C-J, Loo JA, and Garrell RL. “Integrated sample purification in EWOD-MALDI-MS.” Special Publication - Royal Society of Chemistry 2004; 297 (Micro Total Analysis Systems 2004, Volume 2): 204-206.

Xiao GG, Nel AE , and Loo JA. “Nitrotyrosine-Modified Proteins and Oxidative Stress Induced by Diesel Exhaust Particles.” Electrophoresis 2005; 26: 280-292.

Wheeler AR, Moon H, Bird CA, Ogorzalek Loo RR, Kim CJ, Loo JA, and Garrell RL. “Digital Microfluidics with In-line Sample Purification for Proteomics Analyses with MALDI-MS.” Anal Chem 2005; 77: 534-540.

Ogorzalek Loo RR, Hayes R, Yang Y, Hung F, Ramachandran P, Kim N, Gunsalus R, and Loo JA. “Top-Down, Bottom-Up, and Side-to-Side Proteomics with Virtual 2-D Gels.” Int J Mass Spectrom 2005; 240: 317-325.

Kani K, Warren CM, Kaddis CS, Loo JA, and Landgraf R. “Oligomers of ErbB3 Have Two Distinct Interfaces That Differ in Their Sensitivity to Disruption by Heregulin.” J Biol Chem 2005; 280: 8238-8247.

Hu S, Xie Y, Ramachandran P, Ogorzalek Loo RR, Li Y, Loo JA, and Wong DT. “Large-Scale Identification of Human Oral Fluid Proteins by Liquid Chromatography-Mass Spectrometry.” Proteomics 2005; 5: 1714-1728.

Wang M, Xiao GG, Li N, Xie Y, Loo JA, and Nel AE “Use of a Fluorescent Phosphoprotein Dye to Characterize Oxidative Stress-induced Signaling Pathway Components in Macrophage and Epithelial Cultures Exposed to Diesel Exhaust Particle Chemicals.” Electrophoresis 2005; 26: 2092-2108.

Loo JA, Berhane B, Kaddis CS, Wooding KM, Xie Y, Kaufman SL, and Chernushevich IV. “Electrospray Ionization Mass Spectrometry and Ion Mobility Analysis of the 20S Proteasome Complex.” J Am Soc Mass Spectrom 2005; 16: 998-1008.

Gomes AV, Zong C, Edmondson RD, Berhane BT, Wang G-W, Le S, Young G, Zhang J, Vondriska TM, Whitelegge JP, Jones RC, Joshua IG, Thyparambil S, Pantaleon D, Qiao J, Loo J, and Ping P. “The Murine Cardiac 26S Proteasome: An Organelle Awaiting Exploration.” Ann NY Acad Sci 2005; 1047: 197–207.

Leikina E, Delanoe-Ayari H, Melikov KC, Cho M-S, Chen A, Waring AJ, Wang W, Xie Y, Loo JA, Lehrer RI, and Chernomordik LV. “Host-Defense Carbohydrate-Binding Molecules Can Inhibit Viral Fusion and Entry by Crosslinking Membrane Glycoproteins.” Nature Immunol 2005; 6: 995-1001.

Divakaruni AV, Ogorzalek Loo RR, Xie Y, Loo JA, and Gober JW. “The Cell-Shape Protein MreC Interacts With Extracytoplasmic Proteins Including Peptidoglycan Assembly Complexes in Caulobacter crescentus .” Proc Natl Acad Sci USA 2005; 102: 18602-18607.

Ramachandran P, Boontheung P, Xie Y, Sondej M, Wong DT, and Loo JA. “Identification of N-Linked Glycoproteins in Human Saliva by Glycoprotein Capture and Mass Spectrometry.” J Proteome Res, 2006; 5: 1493-1503.