Proteome and Differential Expression Analysis of Membrane and Cytosolic Proteins from Mycobacterium avium subsp. paratuberculosis Strains K-10 and 187

USDA-ARS, National Animal Disease Center, Ames IA. 50010

^* To whom correspondence should be addressed. Email: jstabel{at}nadc.ars.usda.gov.

	Abstract

Little is known of the protein expression in Mycobacterium avium subspecies paratuberculosis (MAP) and how this contributes to pathogenesis. In the present study, proteins from both membranes and cytosol were prepared from two strains of MAP; a laboratory-adapted strain K-10 and a recent isolate, strain 187, obtained from a cow exhibiting clinical signs of Johnes disease. SDS-PAGE of cytosol and membrane proteins from K-10 and 187 showed marked differences in protein expression. Relative levels of protein expression from both MAP strains were measured using amine-reactive isobaric tagging reagents (iTRAQ) and tandem mass spectroscopy. Protein identification and relative expression data were obtained for 874 membrane and cytosolic proteins from the MAP proteome. These data showed a number of significant differences in protein expression between K-10 and the clinical isolate 187. Examples of proteins expressed at higher levels in strain 187 as compared to strain K-10 are AtpC, RpoA and several proteins involved in fatty acid biosynthesis. In contrast, proteins such as AhpC and several proteins involved in nitrogen metabolism were expressed at higher levels in strain K-10 as compared to strain 187. These data may provide insights into the proteins whose expression is important in natural infection but are modified once MAP is adapted to laboratory cultivation. Results from these studies will provide tools for developing a better understanding of MAP infection in the host, and offer potential as diagnostic reagents and vaccine candidates.