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Title: Crystal Structure of An Electron Transfer Complex Between Aromatic Amine Dehydrogenase And Azurin From Alcaligenes Faecalis

Abstract

No abstract prepared.

Authors:
; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
897447
Report Number(s):
SLAC-REPRINT-2006-176
TRN: US200705%%325
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: Biochem.45:13500, 2006
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; AMINES; AROMATICS; CRYSTAL STRUCTURE; ELECTRON TRANSFER; OXIDOREDUCTASES; Other,OTHER

Citation Formats

Sukumar, N., Chen, Z.W., Ferrari, D., Merli, A., Rossi, G.L., Bellamy, H.D., Chistoserdov, A., Davidson, V.L., Mathews, F.S., and /Washington U., St. Louis /Parma U. /SLAC, SSRL /Mississippi U.. Crystal Structure of An Electron Transfer Complex Between Aromatic Amine Dehydrogenase And Azurin From Alcaligenes Faecalis. United States: N. p., 2007. Web.
Sukumar, N., Chen, Z.W., Ferrari, D., Merli, A., Rossi, G.L., Bellamy, H.D., Chistoserdov, A., Davidson, V.L., Mathews, F.S., & /Washington U., St. Louis /Parma U. /SLAC, SSRL /Mississippi U.. Crystal Structure of An Electron Transfer Complex Between Aromatic Amine Dehydrogenase And Azurin From Alcaligenes Faecalis. United States.
Sukumar, N., Chen, Z.W., Ferrari, D., Merli, A., Rossi, G.L., Bellamy, H.D., Chistoserdov, A., Davidson, V.L., Mathews, F.S., and /Washington U., St. Louis /Parma U. /SLAC, SSRL /Mississippi U.. Fri . "Crystal Structure of An Electron Transfer Complex Between Aromatic Amine Dehydrogenase And Azurin From Alcaligenes Faecalis". United States. doi:.
@article{osti_897447,
title = {Crystal Structure of An Electron Transfer Complex Between Aromatic Amine Dehydrogenase And Azurin From Alcaligenes Faecalis},
author = {Sukumar, N. and Chen, Z.W. and Ferrari, D. and Merli, A. and Rossi, G.L. and Bellamy, H.D. and Chistoserdov, A. and Davidson, V.L. and Mathews, F.S. and /Washington U., St. Louis /Parma U. /SLAC, SSRL /Mississippi U.},
abstractNote = {No abstract prepared.},
doi = {},
journal = {Biochem.45:13500, 2006},
number = ,
volume = ,
place = {United States},
year = {Fri Jan 12 00:00:00 EST 2007},
month = {Fri Jan 12 00:00:00 EST 2007}
}
  • The EF1143 protein from Enterococcus faecalis is a distant homolog of deoxynucleotide triphosphate triphosphohydrolases (dNTPases) from Escherichia coli and Thermus thermophilus. These dNTPases are important components in the regulation of the dNTP pool in bacteria. Biochemical assays of the EF1143 dNTPase activity demonstrated nonspecific hydrolysis of all canonical dNTPs in the presence of Mn{sup 2+}. In contrast, with Mg{sup 2+} hydrolysis required the presence of dGTP as an effector, activating the degradation of dATP and dCTP with dGTP also being consumed in the reaction with dATP. The crystal structure of EF1143 and dynamic light scattering measurements in solution revealed amore » tetrameric oligomer as the most probable biologically active unit. The tetramer contains four dGTP specific allosteric regulatory sites and four active sites. Examination of the active site with the dATP substrate suggests an in-line nucleophilic attack on the {alpha}-phosphate center as a possible mechanism of the hydrolysis and two highly conserved residues, His-129 and Glu-122, as an acid-base catalytic dyad. Structural differences between EF1143 apo and holo forms revealed mobility of the {alpha}3 helix that can regulate the size of the active site binding pocket and could be stabilized in the open conformation upon formation of the tetramer and dGTP effector binding.« less
  • Spectroscopic and electrochemical studies, incorporating electronic spectra, electron paramagnetic resonance (EPR) spectra, resonance Raman (RR) spectra, and measurements of the redox potential, have been carried out on the blue copper protein azurin, from Alcaligenes denitrificans. These data are correlated with the refined crystal structure of this azurin and with corresponding data for other blue copper proteins. The electronic spectrum the EPR spectral parameters and the resonance Raman spectrum are similar to those obtained from other azurins and from plastocyanins. Both the electronic spectrum and the EPR spectrum are unchanged over the pH range 4-10.5, but major changes occur above pHmore » 12 and below pH 3.5. In the RR spectrum the Cu-S stretching mode is shown to contribute to all of the five principal RR peaks. Deuterium substitution produces shifts in at least seven of the peaks. Measurements of the redox potential, using spectroelectrochemical methods, over the temperature range 4.8-40.0 /sup 0/C, give values for ..delta..H/sup 0/' and ..delta..S/sup 0/' of -55.6 kJ mol/sup -1/ and -97.0 J K/sup -1/ mol/sup -1/, respectively. The redox potential of A. denitrificans azurin at pH 7.0, E/sup 0/, is 276 mV. These data are interpreted in terms of a copper site, in azurin, comprising three strong bonds, in an approximately trigonal plane, from Cys-112, His-46, and His-117 and much longer axial approaches from Met-121 and the peptide carbonyl oxygen of Gly-45. Spectral differences within the azurin family and between azurin and plastocyanin are attributed to differences in the strengths of these axial interactions. On the other hand, the relative constancy of the EPR parameters between azurin and plastocyanin suggests they are not strongly influenced by weakly interacting axial groups.« less
  • No abstract prepared.
  • The authors have measured the /sup 13/C kinetic isotope effect at pH 4.0, 5.0, 6.0, and 6.5 and in D/sub 2/O at pH 5.0 and the rate of D-H exchange of the alpha and beta protons of aspartic acid in D/sub 2/O at pH 5.0 for the reaction catalyzed by the enzyme aspartate beta-decarboxylase from Alcaligenes faecalis. The /sup 13/C kinetic isotope effect, with a value of 1.0099 +/- 0.0002 at pH 5.0, is less than the intrinsic isotope effect for the decarboxylation step, indicating that the decarboxylation step is not entirely rate limiting. The authors have been able tomore » estimate probable values of the relative free energies of the transition states of the enzymatic reaction up to and including the decarboxylation step from the /sup 13/C kinetic isotope effect and the rate of D-H exchange of alpha-H. The pH dependence of the kinetic isotope effect reflects the pKa of the pyridine nitrogen of the coenzyme pyridoxal 5'-phosphate but not that of the imine nitrogen. A mechanism is proposed for the exchange of aspartate beta-H that is consistent with the stereochemistry suggested earlier.« less