title: Impact of expression of EMP enzymes on glucose metabolism in Zymomonas mobilis.
abstract: Zymomonas mobilis is the only known microorganism that utilizes the Entner-Doudoroff (ED) pathway anaerobically. In this work, we investigated whether the overexpression of a phosphofructokinase (PFK), the only missing Embden-Meyerhof-Parnas (EMP) pathway enzyme, could establish the pathway in this organism. Introduction of a pyrophosphate-dependent PFK, along with co-expression of homologous fructose-1,6-bisphosphate aldolase and triosephosphate isomerase, did not result in an EMP flux to any appreciable level. However, the metabolism of glucose was impacted significantly. Eight percent of glucose was metabolized to form a new metabolite, dihydroxyacetone. Reducing flux through the ED pathway by as much as 40 % through antisense of a key enzyme, ED aldolase, did not result in a fully functional EMP pathway, suggesting that the ED pathway, especially the lower arm, downstream from glyceraldehyde-3-phosphate, is very rigid, possibly due to redox balance.
authors.affiliation: School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0100, USA. rchen@chbe.gatech.edu
authors.forename: Rachel Ruizhen
authors.initials: RR
authors.lastname: Chen
authors.forename: Manoj
authors.initials: M
authors.lastname: Agrawal
authors.forename: Zichao
authors.initials: Z
authors.lastname: Mao
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D003001:Cloning, Molecular; D004098:Dihydroxyacetone / Q000378:metabolism; D011756:Diphosphates / Q000032:analysis* / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005285:Fermentation; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics / Q000378:metabolism; D005798:Genes, Bacterial; D005947:Glucose / Q000378:metabolism*; D006019:Glycolysis; D025221:Phosphofructokinases / Q000235:genetics / Q000378:metabolism; D014305:Triose-Phosphate Isomerase / Q000235:genetics / Q000378:metabolism; D017355:Zymomonas / Q000201:enzymology* / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D011756:Diphosphates; C107241:diphosphoric acid; D025221:Phosphofructokinases; D005634:Fructose-Bisphosphate Aldolase; D014305:Triose-Phosphate Isomerase; D005947:Glucose; D004098:Dihydroxyacetone