S-layer protein production by Corynebacterium strains is dependent on the carbon source

Abstract

Three strains of Corynebacterium producing various amounts of PS2 S-layer protein were studied. For all strains, more PS2 was produced if the bacteria were grown in minimal medium supplemented with lactate than if they were grown in minimal medium supplemented with glucose. The consumption of substrate and PS2 production was studied in cultures with mixed carbon sources. It was found that the inhibitory effect of glucose consumption was stronger than the stimulatory effect of lactate in one strain, but not in the other two strains. The regulation of gene expression involved in S-layer formation may involve metabolic pathways, which probably differ between strains. S-layer organization was also studied by freeze-fracture electron microscopy. It was found that low levels of PS2 production correlated with the partial covering of the cell surface by a crystalline array. Finally, it was found that PS2 production was mainly regulated by changes in gene expression and that secretion was probably not a limiting step in PS2 accumulation.

The surface (S)-layer gene cspB of Corynebacterium glutamicum is transcriptionally activated by a LuxR-type regulator and located on a 6 kb genomic island absent from the type strain ATCC 13032

“…Furthermore, real-time RT-PCR revealed that cg2831 and the cspB gene were expressed at higher rates during exponential growth than during stationary phase. In earlier studies, Soual-Hoebeke et al (1999) have demonstrated that the amount of S-layer protein is dependent on the growth phase of C. glutamicum and is related to the environmental stimulus of the carbon source available within the growth medium. For instance, the use of lactate as carbon source results in an enhanced formation of the S-layer, and, as a consequence thereof, C. glutamicum cells are densely covered by an ordered S-layer lattice.…”

“…Subsequent studies have demonstrated that the amount of S-layer protein synthesized by C. glutamicum is dependent on the carbon source of the growth medium (Soual-Hoebeke et al, 1999). In particular, the addition of lactate to the growth medium has a stimulatory effect on PS2 production as well as on S-layer formation, whereas an inhibitory effect on PS2 synthesis is observed when glucose is used as carbon source.…”

“…Furthermore, weak similarity (32 % identity within a stretch of 77 amino acids) was detected to the ATP-dependent transcriptional activator MalT of E. coli that binds to the asymmetrical operator sequence GGGGA( T / G )GAGG in front of several genes belonging to the maltose regulon (Vidal-Ingigliardi et al, 1991). Although the similarity of Cg2831 from C. glutamicum to MalT from E. coli is low, it is nevertheless worth mentioning in view of earlier observations that the expression of the S-layer is dependent on the carbon source of the growth medium (Soual-Hoebeke et al, 1999). Additionally, the sequence motif GGGGATGGGT, showing striking similarity to the MalT operator, was identified upstream of the cspB promoter region (Fig.…”

“…In particular, the addition of lactate to the growth medium has a stimulatory effect on PS2 production as well as on S-layer formation, whereas an inhibitory effect on PS2 synthesis is observed when glucose is used as carbon source. On the basis of these observations, a relationship between S-layer formation, carbohydrate metabolism and the physiological status of the cell in general has been suggested (Soual-Hoebeke et al, 1999).…”

Regulation of ldh expression during biotin-limited growth of Corynebacterium glutamicum

“…The promoterprobe vector pMF2 (Soual-Hoebeke et al, 1999) was used for construction of transcriptional fusions of the ldh promoter region or of the sugR-cg2116 promoter region and the promoterless lacZ gene. Plasmid pMF2 was first digested with EcoRI and BamHI and purified.…”