title: Influence of SigB inactivation on Corynebacterium glutamicum protein secretion.
abstract: The non-essential Corynebacterium glutamicum sigma factor, sigB, modulates global gene expression during the transition from exponential growth to the stationary phase. Utilizing a signal peptide derived from C. glutamicum R CgR_0949, a sigB disruption mutant able to secrete 3- to 5-fold more green fluorescence protein (GFP) and α-amylase than the wild type strain was isolated. The signal peptide selectively enabled the mutant to produce greater amounts of both proteins, which were in turn secreted in culture medium in greater quantities than previously acknowledged. A peak GFP productivity of 2.8 g/l was attained, representing the highest GFP productivity reported in C. glutamicum to date. CgR_0949 signal sequence length (30 residues), type (Tat) or the target protein identity (GFP or α-amylase) had no measurable effect on the magnitude of the protein accumulation and consequent secretion. It therefore follows that actual experimentation remains the fastest way to identify suitable signal sequences in C. glutamicum. More secretion studies may reveal even greater secretion productivity by C. glutamicum and consequently present an attractive avenue to further enhance the utility of C. glutamicum as an industrial workhorse.
authors.affiliation: Microbiology Research Group, Research Institute of Innovative Technology for the Earth (RITE), 9-2, Kizugawadai, Kizugawa, Kyoto 619-0292, Japan.
authors.forename: Keiro
authors.initials: K
authors.lastname: Watanabe
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Teramoto
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Suzuki
authors.forename: Masayuki
authors.initials: M
authors.lastname: Inui
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yukawa
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D048230:Corynebacterium glutamicum / Q000235:genetics* / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D017930:Genes, Reporter; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D021382:Protein Sorting Signals; D012808:Sigma Factor / Q000235:genetics*; D000516:alpha-Amylases / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D021382:Protein Sorting Signals; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D049452:Green Fluorescent Proteins; D000516:alpha-Amylases