A Combinatorial Approach To Study Cytochrome P450 Enzymes for De Novo Production of Steviol Glucosides in Baker's Yeast.

Biosynthesis of steviol glycosides in planta proceeds via two cytochrome P450 enzymes (CYPs): kaurene oxidase (KO) and kaurenoic acid hydroxylase (KAH). KO and KAH function in succession with the support of a NADPH-dependent cytochrome P450 reductase (CPR) to convert kaurene to steviol. This work describes a platform for recombinant production of steviol glucosides (SGs) in Saccharomyces cerevisiae, demonstrating the full reconstituted pathway from the simple sugar glucose to the SG precursor steviol.

Down-regulation of porins by a small RNA bypasses the essentiality of the regulated intramembrane proteolysis protease RseP in Escherichia coli.

Adaptation to extracytoplasmic stress in Escherichia coli depends on the activation of sigmaE, normally sequestered by the membrane protein RseA. SigmaE is released in response to stress through the successive RseA cleavage by DegS and the RIP protease RseP. SigmaE and proteases that free it from RseA are essential.

A small bacterial RNA regulates a putative ABC transporter.

A small noncoding bacterial ribonucleic acid of 62-64 nucleotides, RydC, was identified in the genomes of Escherichia coli, Salmonella, and Shigella. In vivo, RydC binds to the RNA-binding protein Hfq, and it is unstable when Hfq is absent. Mobility assays reveal that complex formation between RydC and Hfq is specific, with an apparent binding constant of approximately 300 nm.