PII Signal Transduction Protein GlnK Alleviates Feedback Inhibition of N -Acetyl- l -Glutamate Kinase by l -Arginine in Corynebacterium glutamicum

Abstract

Corynebacteria are safe industrial producers of diverse amino acids, including l -glutamic acid and l -arginine. In this study, we showed that PII protein GlnK played an important role in l -glutamic acid and l -arginine biosynthesis in C. glutamicum . Through clarifying the molecular mechanism of CgGlnK in l -arginine biosynthesis, the novel interaction between CgGlnK and CgNAGK was revealed. The alleviation of l -arginine inhibition of CgNAGK reached approximately 48.21% by CgGlnK addition, and the semi-inhibition constant of CgNAGK increased 1.4-fold. Furthermore, overexpression of glnK in a high-yield l -arginine-producing strain and fermentation of the recombinant strain in a 5-liter bioreactor led to a remarkably increased production of l -arginine, 49.978 g/liter, which was about 22.61% higher than that of the initial strain. In conclusion, this study provides a new strategy for modifying amino acid biosynthesis in C. glutamicum .