|Influence of SigB inactivation on Corynebacterium glutamicum protein secretion.
Appl. Microbiol. Biotechnol. 97: 4917-4926. 2013.
K. Watanabe, H. Teramoto, N. Suzuki, M. Inui and H. Yukawa.
|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.