Identifying Biomarkers and Mechanisms of Toxic Metal Stress with Global Proteomics

Miller, Susan M.

关键词: Hg toxicity;    Hg-protein adducts;    mass spectrometry;    Hg isotope signature;    mer operon;   

DOI  :  10.2172/1038453
RP-ID  :  DOE/ER/64409-Final
PID  :  OSTI ID: 1038453
Others  :  Other: 0013347

学科分类：生物科学（综合）

美国|英语

来源: SciTech Connect

【 摘 要 】

Hg is a wide-spread contaminant in the environment and is toxic in all of its various forms. Data suggest that RHg+ and Hg2+ are toxic in two ways. At low levels, Hg species appear to disrupt membrane-bound respiration causing a burst of reactive oxygen species (ROS) that further damage the cell. At higher Hg concentrations, RHg+ and Hg2+ may form adducts with cysteine- and selenocysteine-containing proteins in all cellular compartments resulting in their inactivation. Although these mechansims for toxicity are generally accepted, the most sensitive targets associated with these mechanisms are not well understood. In this collaborative project involving three laboratories at three institutions, the overall goal was to develop of a mass spectrometry-based global proteomics methodology that could be used to identify Hg-adducted (and ideally, ROS-damaged) proteins in order to address these types of questions. The two objectives of this overall collaborative project were (1) to identify, quantify, and compare ROS- and Hg-damaged proteins in cells treated with various Hg species and concentrations to test this model for two mechanisms of Hg toxicity, and (2) to define the cellular roles of the ubiquitous bacterial mercury resistance (mer) locus with regards to how the proteins of this pathway interact to protect other cell proteins from Hg damage. The specific objectives and accomplishments of the Miller lab in this project included: (1) Development of algorithms for analysis of the Hg-proteomic mass spectrometry data to identify mercury adducted peptides and other trends in the data. (2) Investigation of the role of mer operon proteins in scavenging Hg(II) from other mer pathway proteins as a means of protecting cellular proteins from damage.