Bioorthogonal proteomics of 15-hexadecynyloxyacetic acid chemical reporter reveals preferential targeting of fatty acid modified proteins and biosynthetic enzymes.

Jacob S Yount, Guillaume Charron, Howard C Hang

Index: Bioorg. Med. Chem. 20(2) , 650-4, (2012)

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Abstract

Chemical reporters are powerful tools for the detection and discovery of protein modifications following cellular labeling. The metabolism of alkyne- or azide-functionalized chemical reporters in cells can influence the efficiency and specificity of protein targeting. To evaluate the effect of degradation of chemical reporters of protein fatty acylation, we synthesized 15-hexadecynyloxyacetic acid (HDYOA), a reporter that was designed to be resistant to β-oxidation, and compared its ability to label palmitoylated proteins with an established reporter, 17-octadecynoic acid (ODYA). HDYOA was able to label known candidate S-palmitoylated proteins similarly to ODYA. Accordingly, bioorthogonal proteomic analysis demonstrated that 70% of proteins labeled with ODYA were also labeled with HDYOA. However, the proteins observed differentially in our proteomic studies suggested that a portion of ODYA protein labeling is a result of β-oxidation. In contrast, downstream enzymes involved in β-oxidation of fatty acids were not targeted by HDYOA. Since HDYOA can label S-palmitoylated proteins and is not utilized by downstream β-oxidation pathways, this fatty acid chemical reporter may be particularly useful for bioorthogonal proteomic studies in cell types metabolically skewed toward fatty acid breakdown.Copyright © 2011 Elsevier Ltd. All rights reserved.