RRC ID 80718
Author Kurihara S, Kato K, Asada K, Kumagai H, Suzuki H.
Title A putrescine-inducible pathway comprising PuuE-YneI in which gamma-aminobutyrate is degraded into succinate in Escherichia coli K-12.
Journal J Bacteriol
Abstract Gamma-aminobutyrate (GABA) is metabolized to succinic semialdehyde by GABA aminotransferase (GABA-AT), and the succinic semialdehyde is subsequently oxidized to succinate by succinic semialdehyde dehydrogenase (SSADH). In Escherichia coli, there are duplicate GABA-ATs (GabT and PuuE) and duplicate SSADHs (GabD and YneI). While GabT and GabD have been well studied previously, the characterization and expression analysis of PuuE and YneI are yet to be investigated. By analyzing the amino acid profiles in cells of DeltapuuE and/or DeltagabT mutants, this study demonstrated that PuuE plays an important role in GABA metabolism in E. coli cells. The similarity of the amino acid sequences of PuuE and GabT is 67.4%, and it was biochemically demonstrated that the catalytic center of GabT is conserved as an amino acid residue important for the enzymatic activity in PuuE as Lys-247. However, the regulation of expression of PuuE is significantly different from that of GabT. PuuE is induced by the addition of putrescine to the medium and is repressed by succinate and low aeration conditions; in contrast, GabT is almost constitutive. Similarly, YneI is induced by putrescine, while GabD is not. For E. coli, PuuE is important for utilization of putrescine as a sole nitrogen source and both PuuE and YneI are important for utilization of putrescine as a sole carbon source. The results demonstrate that the PuuE-YneI pathway was a putrescine-inducible GABA degradation pathway for utilizing putrescine as a nutrient source.
Volume 192(18)
Pages 4582-91
Published 2010-9-1
DOI 10.1128/JB.00308-10
PII JB.00308-10
PMID 20639325
PMC PMC2937417
MeSH 4-Aminobutyrate Transaminase / genetics 4-Aminobutyrate Transaminase / metabolism Escherichia coli K12 / metabolism* Escherichia coli Proteins / genetics Escherichia coli Proteins / metabolism* Gene Expression Regulation, Bacterial / drug effects Gene Expression Regulation, Bacterial / genetics Models, Biological Putrescine / pharmacology* Signal Transduction / drug effects Signal Transduction / genetics Succinate-Semialdehyde Dehydrogenase / genetics Succinate-Semialdehyde Dehydrogenase / metabolism Succinic Acid / metabolism* gamma-Aminobutyric Acid / metabolism*
IF 3.006
Prokaryotes E. coli ME9997 ME9998 ME9999 ME10000 ME10001 ME10002 ME10003 ME10004 ME10005