globomycin

Signal peptidase II (LspA)
Gram-negative/Gram-positive bacteria

Globomycin is capable of inhibiting the growth of S. melliferum. The MICs are 6.25 µM (4.1 µg/mL) for strain BC3 and 12.5 µM (8.2 µg/mL) for strain B88.
Globomycin can interfere with the processing of bacterial lipoproteins by inhibition of signal peptidase II in gracilicutes (Gram-negative eubacteria) and firmicutes (Gram-positive eubacteria).
In B. diminuta DS010 cells, in the Globomycin-treated cultures most of the organophosphate hydrolase (OPH) accumulates in the cytoplasmic fraction in an unprocessed form. This is in contrast with the untreated cells where very little precursor was detectable. Moreover, there is substantially less mature OPH detectable in the membrane fraction following Globomycin treatment. The OPH signal peptide contains an invariant cysteine residue at the junction of the signal peptidase (Spase) cleavage site along with a well conserved lipobox motif. Substitution of the conserved lipobox cysteine to serine resulted in release of OPH into the periplasm, confirming that OPH is a lipoprotein.