Table 1.
Missense mutations in lcrV codon 327 block Yersinia pestis type III secretion
| Y. pestis strain | Plasmid | % type III secretion ([S]/[S+P])a |
|
|---|---|---|---|
| YopE | LcrV | ||
| KIM D27 (wild type) | plcrVD27 | 36.6 | 28.3 |
| KIM D27 (wild type) | plcrV*327R | 1.3 | 12.6 |
| KIM D27 (wild type) | plcrV*327W | 1.2 | 10.3 |
| KLD29 (ΔlcrV) | None | 1.7 | NDb |
| KLD29 (ΔlcrV) | plcrVD27 | 33.2 | 36.2 |
a
Type III secretion of Y. pestis was measured after 3 h of growth in cultures that were grown in media with chelated calcium ions at 37°C. Following centrifugation, the extracellular medium was separated into the supernatant (S) and the bacterial pellet (P), and proteins in both fractions were precipitated with trichloroacetic acid and analyzed by immunoblotting with specific antibodies against the type III secretion substrates YopE and LcrV. Secretion was quantified by calculating the percent amount of secreted protein [S] derived from protein in both the medium and the pellet [S+P].
b
ND, no immunoreactive signal detected.