Glutamicum, which includes efflux systems for L-lysine, L-arginine, L-threonine, L-cysteine, L-leucine, L-isoleucine, and L-valine (Eggeling and Sahm, 2003). Hashimoto et al. lately showed that L-glutamate, L-aspartate and L-phenylalanine are secreted by means of a mechano-sensitive channel by passive diffusion in C. glutamicum (Hashimoto et al., 2012). In the past, the export of amino acids by bacteria was believed to be an artificial outcome of industrial overproduction and to possess no biological relevance. But, next to regulation of the biosynthesis of an amino acid and degradation, the corresponding export could possibly be an important possibility to sustain amino acid homoeostasis, specifically in peptide-rich environments (Eggeling and Sahm, 2003). Genes for histidine utilization, that are present in several pathogenic Corynebacterium species, are missing in C. glutamicum (Schr er et al., 2012). However, Bellmann and colleagues (2001) demonstrated the capacity of C. glutamicum to export histidine, which may possibly allow to sustain histidine homoeostasis in an atmosphere wealthy in histidine-containing peptides. Addition of two mM His-Ala dipeptide to a C. glutamicum culture resulted inside a steady raise of external histidine concentration (Bellmann et al., 2001). The export, on the other hand, seems to be rather inefficient as internal histidine concentration rises from zero to 200 mM right after addition of the dipeptide (Bellmann et al., 2001). Considering that C. glutamicum will not secrete any peptidases (Erdmann et al., 1993), the only explanation for the rising external histidine2013 The Authors. Microbial Biotechnology published by John Wiley Sons Ltd and Society for Applied Microbiology, Microbial Biotechnology, 7, 5Histidine in C. glutamicum concentration is export of histidine that was cleaved of from the dipeptide itracellularly. Nevertheless, no candidate gene encoding the exporter has been proposed so far. Interestingly, histidine acts as a co-inducers of lysE transcription, a gene encoding the L-lysine and L-arginine efflux method in C.Anti-Mouse NK1.1 Antibody glutamicum, even though histidine will not be exported by LysE (Bellmann et al.Varenicline Tartrate , 2001). There is certainly no explanation, why histidine acts as co-inducer of the exporter, which can be unable to export L-histidine. In reality, this may well lead to a disadvantageous predicament for the cell as high histidine concentrations may well trigger efflux of L-lysine and L-arginine despite the fact that their concentrations are low.PMID:32261617 This unfavorable impact, nonetheless, could possibly somehow be counteracted by the high Km value of 20 mM for L-lysine export (Br r and Kr er, 1991).Acknowledgements R. K. Kulis-Horn is supported by a CLIB-GC (Graduate Cluster Industrial Biotechnology) Phd grant co-funded by the Ministry of Innovation, Science and Investigation from the federal state of North Rhine-Westphalia (MIWF). This work was part of the SysEnCor research project (Grant 0315598E) funded by the German Federal Ministry of Education and Research (BMBF). We thank Katharina Pfeifer-Sancar and Dr. Christian R kert for giving unpublished RNA-Seq information for C. glutamicum. Additional thanks goes to Elisabeth Zelle (Investigation Centre J ich) for aid with metabolic modelling of C. glutamicum.Conflict of interest None declared.
Many integral and peripheral membrane proteins involved in signal transduction or membrane trafficking is often subjected to covalent lipid modifications, such as myristoylation, farnesylation, prenylation and S-acylation. S-acylation (also called S-palmitoylation) could be the attachment of palmitic or stearic acid t.