RRC ID 35201
Author Kim J, Copley SD.
Title Why metabolic enzymes are essential or nonessential for growth of Escherichia coli K12 on glucose.
Journal Biochemistry
Abstract The genes encoding metabolic enzymes involved in glucose metabolism, the TCA cycle, and biosynthesis of amino acids, purines, pyrimidines, and cofactors would be expected to be essential for growth of Escherichia coli on glucose because the cells must synthesize all of the building blocks for cellular macromolecules. Surprisingly, 80 of 227 of these genes are not essential. Analysis of why these genes are not essential provides insights into the metabolic sophistication of E. coli and into the evolutionary pressures that have shaped its physiology. Alternative routes enabled by interconnecting pathways can allow a defective step to be bypassed. Isozymes, alternative enzymes, broad-specificity enzymes, and multifunctional enzymes can often substitute for a missing enzyme. We expect that the apparent redundancy in these metabolic pathways has arisen due to the need for E. coli to survive in a variety of habitats and therefore to have a metabolism that allows optimal exploitation of varying environmental resources and synthesis of small molecules when they cannot be obtained from the environment.
Volume 46(44)
Pages 12501-11
Published 2007-11-6
DOI 10.1021/bi7014629
PMID 17935357
MeSH Amino Acids / metabolism Citric Acid Cycle Escherichia coli K12 / enzymology* Escherichia coli K12 / genetics Escherichia coli K12 / growth & development* Gene Expression Regulation, Bacterial Gluconeogenesis / genetics* Glucose / metabolism* Glycolysis / genetics* Isoenzymes / genetics Isoenzymes / physiology Metabolic Networks and Pathways Models, Biological Purines / metabolism Pyrimidines / metabolism
IF 2.997
Times Cited 32
Prokaryotes E. coli Review