scholarly journals Assessing the Role of the Active-site Cysteine Ligand in the Superoxide Reductase fromDesulfoarculus baarsii

2007 ◽  
Vol 282 (30) ◽  
pp. 22207-22216 ◽  
Author(s):  
Christelle Mathé ◽  
Claire O. Weill ◽  
Tony A. Mattioli ◽  
Catherine Berthomieu ◽  
Chantal Houée-Levin ◽  
...  
Keyword(s):  
Active Site ◽  
Superoxide Reductase ◽  
Active Site Cysteine

Characterization of anEscherichia coliSulfite Oxidase Homologue Reveals the Role of a Conserved Active Site Cysteine in Assembly and Function†

Biochemistry ◽  
2005 ◽  
Vol 44 (30) ◽  
pp. 10339-10348 ◽  
Author(s):  
Stephen J. Brokx ◽  
Richard A. Rothery ◽  
Guijin Zhang ◽  
Derek P. Ng ◽  
Joel H. Weiner
Keyword(s):  
Active Site ◽  
Active Site Cysteine ◽  
And Function

scholarly journals Mutagenesis and crystallographic studies of the catalytic residues of the papain family protease bleomycin hydrolase: new insights into active-site structure

2006 ◽  
Vol 401 (2) ◽  
pp. 421-428 ◽  
Author(s):  
Paul A. O'Farrell ◽  
Leemor Joshua-Tor
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Bound Water ◽  
Active Site Residues ◽  
Site Structure ◽  
Active Site Cysteine ◽  
C Terminus ◽  
Bleomycin Hydrolase ◽  
Active Site Mutants

Bleomycin hydrolase (BH) is a hexameric papain family cysteine protease which is involved in preparing peptides for antigen presentation and has been implicated in tumour cell resistance to bleomycin chemotherapy. Structures of active-site mutants of yeast BH yielded unexpected results. Replacement of the active-site asparagine with alanine, valine or leucine results in the destabilization of the histidine side chain, demonstrating unambiguously the role of the asparagine residue in correctly positioning the histidine for catalysis. Replacement of the histidine with alanine or leucine destabilizes the asparagine position, indicating a delicate arrangement of the active-site residues. In all of the mutants, the C-terminus of the protein, which lies in the active site, protrudes further into the active site. All mutants were compromised in their catalytic activity. The structures also revealed the importance of a tightly bound water molecule which stabilizes a loop near the active site and which is conserved throughout the papain family. It is displaced in a number of the mutants, causing destabilization of this loop and a nearby loop, resulting in a large movement of the active-site cysteine. The results imply that this water molecule plays a key structural role in this family of enzymes.

scholarly journals Active site alanine substitutions can convert deubiquitinating enzymes into avid ubiquitin-binding domains

2017 ◽  
Author(s):  
Marie Morrow ◽  
Michael Morgan ◽  
Marcello Clerici ◽  
Katerina Growkova ◽  
Ming Yan ◽  
...  
Keyword(s):  
Active Site ◽  
Tight Binding ◽  
Dominant Negative ◽  
Structural Basis ◽  
Deubiquitinating Enzymes ◽  
Active Site Cysteine ◽  
Binding Domains ◽  
Common Strategy ◽  
Catalytic Cysteine

ABSTRACTA common strategy for studying the biological role of deubiquitinating enzymes (DUBs) in different pathways is to study the effects of replacing the wild type DUB with a catalytically inactive mutant in cells. We report here that a commonly studied DUB mutation, in which the catalytic cysteine is replaced with alanine, can dramatically increase the affinity of some DUBs for ubiquitin. Overexpression of these tight-binding mutants thus has the potential to sequester cellular pools of monoubiquitin and ubiquitin chains. As a result, cells expressing these mutants may display unpredictable dominant negative physiological effects that are not related to loss of DUB activity. The structure of the SAGA DUB module bound to free ubiquitin reveals the structural basis for the 30-fold higher affinity of Ubp8C146A for ubiquitin. We show that an alternative option, substituting the active site cysteine with arginine, can inactivate DUBs while also decreasing the affinity for ubiquitin.

Role of the active-site cysteine of Pseudomonas aeruginosa azurin. Crystal structure analysis of the CuII(Cys112Asp) protein

1997 ◽  
Vol 2 (4) ◽  
pp. 464-469 ◽  
Author(s):  
Salem Faham ◽  
Tadashi J. Mizoguchi ◽  
Elinor T. Adman ◽  
Harry B. Gray ◽  
John H. Richards ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Pseudomonas Aeruginosa ◽  
Structure Analysis ◽  
Active Site ◽  
Crystal Structure Analysis ◽  
Active Site Cysteine

Computational investigations on the catalytic mechanism of maleate isomerase: the role of the active site cysteine residues

2014 ◽  
Vol 16 (24) ◽  
pp. 12462-12474 ◽  
Author(s):  
Hisham M. Dokainish ◽  
Bogdan F. Ion ◽  
James W. Gauld
Keyword(s):  
Active Site ◽  
Catalytic Mechanism ◽  
The State ◽  
Cysteine Residues ◽  
Active Site Cysteine ◽  
Computational Enzymology

Multiscale computational enzymology provides key insights into the state of the substrate-bound active site and roles of its cysteinyl residues.

scholarly journals Conformational H-bonding modulation of the iron active site cysteine ligand of superoxide reductase: absorption and resonance Raman studies

2021 ◽  
Author(s):  
Alain Desbois ◽  
Julien Valton ◽  
Yohann Moreau ◽  
Stéphane Torelli ◽  
Vincent Nivière
Keyword(s):  
Hydrogen Bonds ◽  
Bond Strength ◽  
Active Site ◽  
Resonance Raman ◽  
Fine Tuning ◽  
Superoxide Reductase ◽  
Active Site Cysteine

Superoxide reductase Asn117 residue, by making hydrogen bonds with neighboring residues, enables fine-tuning of the Fe–S(Cys116) bond strength.

Role of the Active Site Cysteine of DpgA, a Bacterial Type III Polyketide Synthase†

Biochemistry ◽  
2004 ◽  
Vol 43 (4) ◽  
pp. 970-980 ◽  
Author(s):  
Claire C. Tseng ◽  
Shaun M. McLoughlin ◽  
Neil L. Kelleher ◽  
Christopher T. Walsh
Keyword(s):  
Active Site ◽  
Polyketide Synthase ◽  
Type Iii Polyketide Synthase ◽  
Type Iii ◽  
Active Site Cysteine ◽  
Bacterial Type

scholarly journals The E2 Ubiquitin Conjugase Rad6 Is Required for the ArgR/Mcm1 Repression of ARG1 Transcription

2002 ◽  
Vol 22 (12) ◽  
pp. 4011-4019 ◽  
Author(s):  
Suzanne D. Turner ◽  
Andrea R. Ricci ◽  
Helen Petropoulos ◽  
Julie Genereaux ◽  
Ilona S. Skerjanc ◽  
...  
Keyword(s):  
Active Site ◽  
Chromatin Immunoprecipitation ◽  
Double Mutant ◽  
Minimal Medium ◽  
Tata Binding Protein ◽  
Rich Medium ◽  
Histone H2b ◽  
Active Site Cysteine ◽  
Ubiquitination Site

ABSTRACT Transcription of the Saccharomyces cerevisiae ARG1 gene is under the control of both positive and negative elements. Activation of the gene in minimal medium is induced by Gcn4. Repression occurs in the presence of arginine and requires the ArgR/Mcm1 complex that binds to two upstream arginine control (ARC) elements. With the recent finding that the E2 ubiquitin conjugase Rad6 modifies histone H2B, we examined the role of Rad6 in the regulation of ARG1 transcription. We find that Rad6 is required for repression of ARG1 in rich medium, with expression increased ∼10-fold in a rad6 null background. Chromatin immunoprecipitation analysis indicates increased binding of TATA-binding protein in the absence of Rad6. The active-site cysteine of Rad6 is required for repression, implicating ubiquitination in the process. The effects of Rad6 at ARG1 involve two components. In one of these, histone H2B is the likely target for ubiquitination by Rad6, since a strain expressing histone H2B with the principal ubiquitination site converted from lysine to arginine shows a fivefold relief of repression. The second component requires Ubr1 and thus likely the pathway of N-end rule degradation. Through the analysis of promoter constructs with ARC deleted and an arg80 rad6 double mutant, we show that Rad6 repression is mediated through the ArgR/Mcm1 complex. In addition, analysis of an ada2 rad6 deletion strain indicated that the SAGA acetyltransferase complex and Rad6 act in the same pathway to repress ARG1 in rich medium.

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