Shewanella oneidensis is of particular interest for research because of its unique ability to use a variety of metals as final respiratory electron acceptors and reduce them into insoluble oxides. A collection of monoclonal antibodies (mAbs) that were prepared towards Escherichia coli RNA polymerase (RNAP) was tested for reactivity with proteins extracted from S. oneidensis. Two polyol-responsive monoclonal antibodies (PR-mAbs) were used to purify RNA polymerase from S. oneidensis using immunoaffinity purification techniques. A collection of mAbs towards E coli sigma subunits was also examined for cross-reactivity with S. oneidensis proteins. Reactions were identified with mAbs to E Coli sigma(70) and sigma(54). These mAbs will be useful tools for immunoaffinity purifying and studying the transcriptional machinery of S. oneidensis. (C) 2007 Elsevier Inc. All rights reserved.