scholarly journals The Conserved Active Site Motif A ofEscherichia coliDNA Polymerase I Is Highly Mutable

2001 ◽  
Vol 276 (22) ◽  
pp. 18836-18842 ◽  
Author(s):  
Akeo Shinkai ◽  
Premal H. Patel ◽  
Lawrence A. Loeb
Keyword(s):  
Active Site ◽  
Active Site Motif ◽  
Polymerase I

scholarly journals Crystal structures of DNA polymerase I capture novel intermediates in the DNA synthesis pathway

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Nicholas Chim ◽  
Lynnette N Jackson ◽  
Anh M Trinh ◽  
John C Chaput
Keyword(s):  
High Resolution ◽  
Dna Synthesis ◽  
Crystal Structures ◽  
Dna Polymerase ◽  
Active Site ◽  
Dna Polymerase I ◽  
Dynamic Nature ◽  
Enzyme Active Site ◽  
Polymerase I ◽  
In Cells

High resolution crystal structures of DNA polymerase intermediates are needed to study the mechanism of DNA synthesis in cells. Here we report five crystal structures of DNA polymerase I that capture new conformations for the polymerase translocation and nucleotide pre-insertion steps in the DNA synthesis pathway. We suggest that these new structures, along with previously solved structures, highlight the dynamic nature of the finger subdomain in the enzyme active site.

An energy charge sensor for balancing RNA polymerase recycling and hibernation

2020 ◽  
Author(s):  
Markus Wahl ◽  
Hao-Hong Pei ◽  
Tarek Hilal ◽  
Zhuo Chen ◽  
Yong-Heng Huang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Active Site ◽  
Genome Stability ◽  
Energy Levels ◽  
Energy Charge ◽  
Coiled Coil ◽  
Main Channel ◽  
Rna Polymerase I ◽  
Secondary Channel ◽  
Polymerase I

Abstract Cellular RNA polymerases can become trapped on DNA or RNA, threatening genome stability and limiting free enzyme pools, or enter dormancy. How RNA polymerase recycling into active states is achieved and balanced with quiescence remains elusive. We structurally analyzed Bacillus subtilis RNA polymerase bound to the NTPase HelD. HelD has two long arms: a Gre cleavage factor-like coiled-coil inserts deep into the RNA polymerase secondary channel, dismantling the active site and displacing RNA; a unique helical protrusion inserts into the main channel, prying β and β’ subunits apart and dislodging DNA, aided by the δ subunit. HelD release depends on ATP, and a dimeric structure resembling hibernating RNA polymerase I suggests that HelD can induce dormancy at low energy levels. Our results reveal an ingenious mechanism by which active RNA polymerase pools are adjusted in response to the nutritional state.

scholarly journals Understanding the Role of Histidine in the GHSxG Acyltransferase Active Site Motif: Evidence for Histidine Stabilization of the Malonyl-Enzyme Intermediate

PLoS ONE ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e109421 ◽  
Author(s):  
Sean Poust ◽  
Isu Yoon ◽  
Paul D. Adams ◽  
Leonard Katz ◽  
Christopher J. Petzold ◽  
...  
Keyword(s):  
Active Site ◽  
Active Site Motif ◽  
Enzyme Intermediate

Inactivation of rat liver RNA polymerases I and II and yeast RNA polymerase I by pyridoxal 5'-phosphate. Evidence for the participation of lysyl residues at the active site

Biochemistry ◽  
1975 ◽  
Vol 14 (22) ◽  
pp. 4907-4911 ◽  
Author(s):  
Joseph Martial ◽  
Josefina Zaldivar ◽  
Paulina Bull ◽  
Alejandro Venegas ◽  
Pablo Valenzuela
Keyword(s):  
Rna Polymerase ◽  
Rat Liver ◽  
Active Site ◽  
Rna Polymerases ◽  
Rna Polymerase I ◽  
Polymerase I

scholarly journals Glutathione-dependent activities of Trypanosoma cruzi p52 makes it a new member of the thiol:disulphide oxidoreductase family

1997 ◽  
Vol 322 (1) ◽  
pp. 43-48 ◽  
Author(s):  
Mireille MOUTIEZ ◽  
Eric QUÉMÉNEUR ◽  
Christian SERGHERAERT ◽  
Valérie LUCAS ◽  
André TARTAR ◽  
...  
Keyword(s):  
Trypanosoma Cruzi ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Reductase Activity ◽  
Redox Balance ◽  
Ribonuclease A ◽  
Physiological Conditions ◽  
Active Site Motif ◽  
Key Enzyme ◽  
Low Rate

Trypanothione:glutathione disulphide thioltransferase of Trypanosoma cruzi (p52) is a key enzyme in the regulation of the intracellular thiolŐdisulphide redox balance by reducing glutathione disulphide. Here we show that p52, like other disulphide oxidoreductases possessing the CXXC active site motif, catalyses the reduction of low-molecular-mass disulphides (hydroxyethyldisulphide) as well as protein disulphides (insulin). However, p52 seems to be a poor oxidase under physiological conditions as evidenced by its very low rate for oxidative renaturation of reduced ribonuclease A. Like thioltransferase and protein disulphide isomerase, p52 was found to possess a glutathione-dependent dehydroascorbate reductase activity. The kinetic parameters were in the same range as those determined for mammalian dehydroascorbate reductases. A catalytic mechanism taking into account both trypanothione- and glutathione-dependent reduction reactions was proposed. This newly characterized enzyme is specific for the parasite and provides a new target for specific chemotherapy.

scholarly journals Side Chains That Influence Fidelity at the Polymerase Active Site ofEscherichia coliDNA Polymerase I (Klenow Fragment)

1999 ◽  
Vol 274 (5) ◽  
pp. 3067-3075 ◽  
Author(s):  
Dana T. Minnick ◽  
Katarzyna Bebenek ◽  
Wendy P. Osheroff ◽  
Robert M. Turner ◽  
Mekbib Astatke ◽  
...  
Keyword(s):  
Active Site ◽  
Side Chains ◽  
Klenow Fragment ◽  
Polymerase I
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