Identification of polypeptides expressed in response to vinyl chloride, ethene, and epoxyethane in Nocardioides sp. strain JS614 by using peptide mass fingerprinting

Abstract

Enzymes expressed in response to vinyl chloride, ethene, and epoxyethane by Nocardioides sp. strain JS614 were identified by using a peptide mass fingerprinting (PMF) approach. PMF provided insight concerning vinyl chloride biodegradation in strain JS614 and extends the use of matrix-assisted laser desorption-ionization time of flight mass spectrometry as a tool to enhance characterization of biodegradation pathways.

FIG. 1.

Representative results of SDS-PAGE with cell extracts from epoxyethane (EPOX)-, vinyl chloride (VC)-, ethene (ETH)-, and acetate (ACE)-grown JS614 cultures and a protein ladder (L). Numbers and arrows indicate sections of the gel that were excised for MALDI-TOF MS analysis and correspond to results presented in Table 1.

FIG. 2.

A representative PMF of the probable AkMO alpha subunit (Noc4807) measured from a protein extract of a VC-grown JS614 culture (a.u., atomic units). The mass spectrum and a complete list of peptide masses that make up the PMF are shown.

FIG. 3.

Diagram of plasmid-encoded region containing ethene/VC biodegradation genes in Nocardioides sp. strain JS614. Genes expressed and translated into protein in response to epoxyethane, VC, or ethene as identified by MALDI-TOF MS and PMF analysis are shaded gray. Genes 4831 to 4844 and the second EaCoMT allele, etnE1, appear to be the result of a duplication of genes 4810 to 4823, evidenced by high amino acid similarities and the conservation of gene orientation. For example, genes 4814 and 4822 share 90 and 86% amino acid similarities, respectively, with genes 4841 and 4833.