title: Excretion of the egl gene product of Pseudomonas solanacearum.
abstract: Pseudomonas solanacearum is an important phytopathogen which excretes a variety of extracellular enzymes. Pulse-chase experiments showed that one of these enzymes, a beta-1,4-endoglucanase (EGL) encoded by the egl gene, is synthesized as a higher-molecular-weight precursor polypeptide (pEGL) which is subsequently excreted into the extracellular medium as a 43-kilodalton mature protein. S1 nuclease transcript mapping and DNA sequence analysis were used to identify the transcription start site and the possible translation start site of egl. Pulse-chase experiments and comparison of the putative NH2-terminal amino acid sequence of pEGL with the actual NH2-terminal amino acid sequence of mature excreted EGL suggested that pEGL has a 45-residue leader sequence preceding the N terminus of EGL which is proteolytically cleaved during export to the extracellular environment. The first 20 residues of the leader sequence resembled a typical lipoprotein signal peptide. The excretion of EGL by P. solanacearum apparently requires a membrane potential since it was blocked by carbonyl cyanide m-chlorophenyl hydrazone.
authors.affiliation: Department of Microbiology, University of Georgia, Athens 30602.
authors.forename: J Z
authors.initials: JZ
authors.lastname: Huang
authors.forename: M
authors.initials: M
authors.lastname: Sukordhaman
authors.forename: M A
authors.initials: MA
authors.lastname: Schell
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D001692:Biological Transport / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism / Q000502:physiology; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011498:Protein Precursors / Q000096:biosynthesis; D021382:Protein Sorting Signals / Q000302:isolation & purification; D011549:Pseudomonas / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D011498:Protein Precursors; D021382:Protein Sorting Signals; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone