Themtlgenes and the mannitol-1-phosphate dehydrogenase fromKlebsiella pneumoniaeKAY2026

Abstract

The mtl operon of Klebsiella pneumoniae KAY2026 (formerly Aerobacter aerogenes 1033-5P14) was shown to contain as the promoter-proximal gene mtlA, encoding a D-mannitol-specific enzyme II transporter (IICBA(Mtl)). This gene is followed by mtlD, coding for a mannitol-1-phosphate dehydrogenase (MtlD, 382 amino acid residues), and mtlR (MtlR, 195 amino acid residues) coding for a putative repressor, gene mtlR overlaps the termination codon of mtlD. The DNA and protein sequences are highly similar to the corresponding genes (81% identical bp) and proteins (79-85% identical amino acids) of Escherichia coli K-12. A truncated form of MtlD lacking the 162 C-terminal amino acid residues still shows 10% dehydrogenase activity which may explain the controversy in the literature concerning the properties of mannitol-phosphate and other medium-length dehydrogenases.

High-yield production of 1,3-propanediol from glycerol by metabolically engineered Klebsiella pneumoniae

“…3 ). Comparing to the other three co-substrates, mannitol utilization pathway produces additionally 1 mol of NADH when mannitol-1-phosphate converts to fructose-6-phosphate [ 32 , 33 ]. Indeed, NADH/NAD + ratio was highest when mannitol was used as co-substrate (Fig.…”

“…To reduce fermentation cost, mannitol consumption should be restricted. Here, we attempted to solve it by decreasing the expression level of mannitol-specific transporter, MtlA (NCBI-Protein ID: AEK00431) by genome editing [ 32 – 34 ]. The 5′-UTR sequence of the mtlA was determined by RBS calculator and then was edited by CRISPR/Cas9 method as described in “ Methods ”.…”