Related ArticlesStudies on ribonucleoside-diphosphate reductase from Escherichia coli. The product dCDP is a competitive inhibitor and functions as a spectroscopic probe for the substrate binding site; demonstration by enzyme kinetics and 1H NMR.
Eur J Biochem. 1992 Sep 15;208(3):631-4
Authors: Shen B, Allard P, Kuprin S, Ehrenberg A
Ribonucleoside-diphosphate reductase (EC 1.17.4.1) from Escherichia coli consists of two protein subunits, R1 of 171.5 kDa and R2 of 86.8 kDa, and catalyzes the reduction of all four common ribonucleoside diphosphates. In a search for ligands that bind weakly to the enzyme active site and may be in fast exchange suitable for NMR studies, we have found that the product dCDP is a competitive inhibitor. Kinetics with CDP as substrate shows Km = 4.8 x 10(-5) M and dCDP inhibits with Ki = 1.6 x 10(-4) M. With an assumed diffusion limited binding rate approximately less than 10(9) M-1s-1, the dissociation rate of dCDP would be approximately less than 10(5) s-1. In 1H-NMR experiments studying linewidths, i.e. spin-spin relaxation, dCDP is indeed demonstrated to be in fast exchange. Enzyme subunit R1 causes a line broadening of dCDP resonances. Unexpectedly less broadening was observed when subunit R2 combined with R1. No paramagnetic interaction from the tyrosyl radical of R2 could be detected. It is concluded that dCDP is a promising NMR probe for studies of active-site properties of the enzyme.
[NMR paper] Refolding of [6-19F]tryptophan-labeled Escherichia coli dihydrofolate reductase in th
Refolding of tryptophan-labeled Escherichia coli dihydrofolate reductase in the presence of ligand: a stopped-flow NMR spectroscopy study.
Related Articles Refolding of tryptophan-labeled Escherichia coli dihydrofolate reductase in the presence of ligand: a stopped-flow NMR spectroscopy study.
Biochemistry. 1998 Jan 6;37(1):387-98
Authors: Hoeltzli SD, Frieden C
Escherichia coli dihydrofolate reductase contains five tryptophan residues that are spatially distributed throughout the protein and located in different secondary structural elements....
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[NMR paper] NMR studies of binding of 5-FdUDP and dCDP to ribonucleoside-diphosphate reductase fr
NMR studies of binding of 5-FdUDP and dCDP to ribonucleoside-diphosphate reductase from Escherichia coli.
Related Articles NMR studies of binding of 5-FdUDP and dCDP to ribonucleoside-diphosphate reductase from Escherichia coli.
Biochim Biophys Acta. 1995 Mar 15;1247(2):284-92
Authors: Roy B, Decout JL, Béguin C, Fontecave M, Allard P, Kuprin S, Ehrenberg A
5-Fluoro-2'-deoxyuridine-5'-diphosphate (5-FdUDP) has been synthesised using an original route, previously applied to the synthesis of natural nucleoside diphosphates. The interaction...
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[NMR paper] Proton NMR of Escherichia coli sulfite reductase: studies of the heme protein subunit
Proton NMR of Escherichia coli sulfite reductase: studies of the heme protein subunit with added ligands.
Related Articles Proton NMR of Escherichia coli sulfite reductase: studies of the heme protein subunit with added ligands.
Biochemistry. 1993 Aug 31;32(34):8782-91
Authors: Kaufman J, Siegel LM, Spicer LD
The heme protein subunit of sulfite reductase (SiR-HP; M(r) 64,000) from Escherichia coli as isolated contains the isobacteriochlorin siroheme exchange-coupled to a cluster in the 2+ oxidation state. SiR-HP in the presence of a suitable...
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[NMR paper] Proton NMR of Escherichia coli sulfite reductase: the unligated hemeprotein subunit.
Proton NMR of Escherichia coli sulfite reductase: the unligated hemeprotein subunit.
Related Articles Proton NMR of Escherichia coli sulfite reductase: the unligated hemeprotein subunit.
Biochemistry. 1993 Mar 23;32(11):2853-67
Authors: Kaufman J, Spicer LD, Siegel LM
The isolated hemeprotein subunit of sulfite reductase (SiR-HP) from Escherichia coli consists of a high spin ferric isobacteriochlorin (siroheme) coupled to a diamagnetic 2+ cluster. When supplied with an artificial electron donor, such as methyl viologen cation radical, SiR-HP...
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[NMR paper] 13C NMR studies of complexes of Escherichia coli dihydrofolate reductase formed with
13C NMR studies of complexes of Escherichia coli dihydrofolate reductase formed with methotrexate and with folic acid.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--linkinghub.elsevier.com-ihub-images-PubMedLink.gif Related Articles 13C NMR studies of complexes of Escherichia coli dihydrofolate reductase formed with methotrexate and with folic acid.
FEBS Lett. 1992 Nov 9;312(2-3):147-51
Authors: Cheung HT, Birdsall B, Feeney J
13C NMR studies of 13C-labelled ligands bound to dihydrofolate reductase provide (DHFR) a powerful means of...
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[NMR paper] Binding of the competitive inhibitor dCDP to ribonucleoside-diphosphate reductase fro
Binding of the competitive inhibitor dCDP to ribonucleoside-diphosphate reductase from Escherichia coli studied by 1H NMR. Different properties of the large protein subunit and the holoenzyme.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles Binding of the competitive inhibitor dCDP to ribonucleoside-diphosphate reductase from Escherichia coli studied by 1H NMR. Different properties of the large protein subunit and the holoenzyme.
Eur J Biochem. 1992 Sep...
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[NMR paper] NMR studies of the activation of the Escherichia coli trp repressor.
NMR studies of the activation of the Escherichia coli trp repressor.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles NMR studies of the activation of the Escherichia coli trp repressor.
Eur J Biochem. 1991 Nov 1;201(3):569-79
Authors: Hyde EI, Ramesh V, Frederick R, Roberts GC
The Escherichia coli trp repressor binds to the trp operator in the presence of tryptophan, thereby inhibiting tryptophan biosynthesis. Tryptophan analogues...
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[NMR paper] NMR studies of the activation of the Escherichia coli trp repressor.
NMR studies of the activation of the Escherichia coli trp repressor.
http://www.ncbi.nlm.nih.gov/corehtml/query/egifs/http:--www3.interscience.wiley.com-aboutus-images-wiley_interscience_pubmed_logo_FREE_120x27.gif Related Articles NMR studies of the activation of the Escherichia coli trp repressor.
Eur J Biochem. 1991 Nov 1;201(3):569-79
Authors: Hyde EI, Ramesh V, Frederick R, Roberts GC
The Escherichia coli trp repressor binds to the trp operator in the presence of tryptophan, thereby inhibiting tryptophan biosynthesis. Tryptophan analogues...