Function of serine-52 and serine-80 in the catalytic mechanism of Escherichia coli aspartate transcarbamoylase

Biochemistry ◽  
1991 ◽  
Vol 30 (9) ◽  
pp. 2535-2542 ◽  
Author(s):  
Wei Xu ◽  
Evan R. Kantrowitz
Keyword(s):  
Escherichia Coli ◽  
Catalytic Mechanism ◽  
Aspartate Transcarbamoylase

scholarly journals Crystal Structure of Escherichia coli Agmatinase: Catalytic Mechanism and Residues Relevant for Substrate Specificity

2021 ◽  
Vol 22 (9) ◽  
pp. 4769
Author(s):  
Pablo Maturana ◽  
María S. Orellana ◽  
Sixto M. Herrera ◽  
Ignacio Martínez ◽  
Maximiliano Figueroa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Conformational Dynamics ◽  
High Specificity ◽  
Arginine Decarboxylase ◽  
Space Groups ◽  
X Ray Crystallography ◽  
High Dynamics ◽  
Dynamics Simulations

Agmatine is the product of the decarboxylation of L-arginine by the enzyme arginine decarboxylase. This amine has been attributed to neurotransmitter functions, anticonvulsant, anti-neurotoxic, and antidepressant in mammals and is a potential therapeutic agent for diseases such as Alzheimer’s, Parkinson’s, and cancer. Agmatinase enzyme hydrolyze agmatine into urea and putrescine, which belong to one of the pathways producing polyamines, essential for cell proliferation. Agmatinase from Escherichia coli (EcAGM) has been widely studied and kinetically characterized, described as highly specific for agmatine. In this study, we analyze the amino acids involved in the high specificity of EcAGM, performing a series of mutations in two loops critical to the active-site entrance. Two structures in different space groups were solved by X-ray crystallography, one at low resolution (3.2 Å), including a guanidine group; and other at high resolution (1.8 Å) which presents urea and agmatine in the active site. These structures made it possible to understand the interface interactions between subunits that allow the hexameric state and postulate a catalytic mechanism according to the Mn2+ and urea/guanidine binding site. Molecular dynamics simulations evaluated the conformational dynamics of EcAGM and residues participating in non-binding interactions. Simulations showed the high dynamics of loops of the active site entrance and evidenced the relevance of Trp68, located in the adjacent subunit, to stabilize the amino group of agmatine by cation-pi interaction. These results allow to have a structural view of the best-kinetic characterized agmatinase in literature up to now.

Importance of a conserved residue, aspartate-162, for the function of Escherichia coli aspartate transcarbamoylase

Biochemistry ◽  
1992 ◽  
Vol 31 (11) ◽  
pp. 3026-3032 ◽  
Author(s):  
Colin J. Newton ◽  
Raymond C. Stevens ◽  
Evan R. Kantrowitz
Keyword(s):  
Escherichia Coli ◽  
Aspartate Transcarbamoylase ◽  
Conserved Residue

scholarly journals Ligand interactions at the active site of aspartate transcarbamoylase from Escherichia coli

Biochemistry ◽  
1986 ◽  
Vol 25 (7) ◽  
pp. 1605-1611 ◽  
Author(s):  
Paul R. Dennis ◽  
M. Vijaya Krishna ◽  
Maria Di Gregorio ◽  
William W. C. Chan
Keyword(s):  
Escherichia Coli ◽  
Active Site ◽  
Aspartate Transcarbamoylase ◽  
Ligand Interactions

scholarly journals Role of 2-Phosphoglycolate Phosphatase of Escherichia coli in Metabolism of the 2-Phosphoglycolate Formed in DNA Repair

2003 ◽  
Vol 185 (19) ◽  
pp. 5815-5821 ◽  
Author(s):  
Maria Teresa Pellicer ◽  
Maria Felisa Nuñez ◽  
Juan Aguilar ◽  
Josefa Badia ◽  
Laura Baldoma
Keyword(s):  
Escherichia Coli ◽  
Dna Repair ◽  
Catalytic Mechanism ◽  
Constitutive Expression ◽  
Catalytic Efficiency ◽  
Phosphoglycolate Phosphatase ◽  
General Metabolism ◽  
Functional Features ◽  
Dna Strand ◽  
Cellular Dna

ABSTRACT The enzyme 2-phosphoglycolate phosphatase from Escherichia coli, encoded by the gph gene, was purified and characterized. The enzyme was highly specific for 2-phosphoglycolate and showed good catalytic efficiency (k cat/Km ), which enabled the conversion of this substrate even at low intracellular concentrations. A comparison of the structural and functional features of this enzyme with those of 2-phosphoglycolate phosphatases of different origins showed a high similarity of the sequences, implying the use of the same catalytic mechanism. Western blot analysis revealed constitutive expression of the gph gene, regardless of the carbon source used, growth stage, or oxidative stress conditions. We showed that this housekeeping enzyme is involved in the dissimilation of the intracellular 2-phosphoglycolate formed in the DNA repair of 3′-phosphoglycolate ends. DNA strand breaks of this kind are caused by agents such as the radiomimetic compound bleomycin. The differential response between a 2-phosphoglycolate phosphatase-deficient mutant and its parental strain after treatment with bleomycin allowed us to connect the intracellular formation of 2-phosphoglycolate with the production of glycolate, which is subsequently incorporated into general metabolism. We thus provide evidence for a salvage function of 2-phosphoglycolate phosphatase in the metabolism of a two-carbon compound generated by the cellular DNA repair machinery.

Sign in / Sign up

Export Citation Format

Share Document