NtSCP1 from tobacco is an extracellular serine carboxypeptidase III that has an impact on cell elongation.

The leaf extracellular space contains several peptidases, most of which are of unknown function. We isolated cDNAs for two extracellular serine carboxypeptidase III genes from tobacco (Nicotiana tabacum), NtSCP1 and NtSCP2, belonging to a phylogenetic clade not yet functionally characterized in plants. NtSCP1 and NtSCP2 are orthologs derived from the two ancestors of tobacco.

Identification of peptidases in Nicotiana tabacum leaf intercellular fluid.

Peptidases in the extracellular space might affect the integrity of recombinant proteins expressed in, and secreted from, plant cells. To identify extracellular peptidases, we recovered the leaf intercellular fluid from Nicotiana tabacum plants by an infiltration-centrifugation method. The activity of various peptidases was detected by an in vitro assay in the presence of specific inhibitors, using BSA and human serum gamma-globulin as substrates.

Expression and secretion of recombinant outer-surface protein A from the Lyme disease agent, Borrelia burgdorferi, in Nicotiana tabacum suspension cells.

The ospA gene of Borrelia burgdorferi codes for an outer membrane lipoprotein, which is a major antigen of the Lyme disease agent. Recombinant OspA vaccines tested so far were expressed in Escherichia coli. In this study, we investigated the expression of a soluble OspA protein in Nicotiana tabacum suspension cells and evaluated the secretion of OspA driven by either its own bacterial signal peptide or a plant signal peptide fused to the amino-terminal cysteine of the mature form.