An experimental study on carbon flow inEscherichia coli as a function of kinetic properties and expression levels of the enzyme phosphoglucomutase

Abstract

Mutants of Escherichia coli deficient in phosphoglucomutase accumulate amylose when the cells are grown on maltose or galactose as carbon source. In the presence of physiological levels of phosphoglucomutase, most of the sugar is catabolized, leading to strongly reduced levels of amylose accumulation. By varying the expression level of heterologous phosphoglucomutase, we show that the minimum level needed to block amylose accumulation corresponds to a phosphoglucomutase activity of 150–600 nmole substrate transformed per min per mg of total soluble protein. Mutant phosphoglucomutases with strongly reduced Vmax values and increased Km values for the substrate glucose‐1‐phosphate or the co‐substrate glucose‐1,6‐diphosphate, could also reduce amylose accumulation, but much higher enzyme expression levels were required. © 1998 John Wiley & Sons, Inc. Biotechnol Bioeng 58:299–302, 1998.

Stochasticity, determinism, and contingency shape genome evolution of endosymbiotic bacteria

“…In addition, several other genes have retention profiles sharing significant direct or reciprocal similarity to Nuo. These include: pgm (a-phosphoglucomutase), which plays a significant role in directing carbon flux 50 ; numerous transporters driven either by ATP or the proton-motive force; and cpdA , a cyclic AMP phosphodiesterase that regulates expression of the cytochrome bd and cbb3 oxidases that function downstream of Nuo or Ndh in the respiratory chain. In addition, the retention pattern of the F 1 F 0 ATP synthase genes is largely reciprocal to that of the gene encoding the ATP-dependent primosomal helicase PriA and the ATP-utilizing sensory kinase (PhoQ), which is known to participate in antimicrobial peptide resistance in Sodalis endosymbionts 51 .…”