| Autor: |
Farchaus JW; Bacteriology Division, U.S. Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, Maryland 21702-5011, USA., Ribot WJ, Downs MB, Ezzell JW |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of bacteriology [J Bacteriol] 1995 May; Vol. 177 (9), pp. 2481-9. |
| DOI: |
10.1128/jb.177.9.2481-2489.1995 |
| Abstrakt: |
Many prokaryotic organisms possess surface layer (S-layer) proteins that are components of the outermost cell envelope. With immunogold labeling, it was demonstrated that the protein extractable antigen 1 (EA1) was localized on the outer surface and specifically to cell wall fragments from Bacillus anthracis which retained the S layer. When grown in rich medium under aerobic conditions, the avirulent strain Delta Sterne-1 released large amounts of EA1 into the medium. This EA1 had no higher-order structure initially but formed two-dimensional crystals under defined conditions. The released EA1 was purified in aqueous buffers with a three-step procedure and found to have a mass of 95 kDa when subjected to denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). N-terminal sequence data revealed exact identity to the first eight residues of the S-layer protein from B. thuringiensis 4045. Gel permeation chromatography of the purified EA1 under nondenaturing conditions revealed a single peak corresponding to a mass of approximately 400 kDa, suggesting that a tetramer or dimer of dimers was the primary species in solution. SDS-PAGE of EA1 purified in the absence of protease inhibitors revealed specific proteolytic processing to an 80-kDa form, which immunoreacted with polyclonal anti-EA1 antibodies. This proteolytic cleavage of EA1 to 80 kDa was duplicated with purified EA1 and the protease trypsin or pronase. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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