Effect of Exchange of the Cysteine Molybdenum Ligand with Selenocysteine on the Structure and Function of the Active Site in Human Sulfite Oxidase

Biochemistry ◽  
2013 ◽  
Vol 52 (46) ◽  
pp. 8295-8303 ◽  
Author(s):  
Stefan Reschke ◽  
Dimitri Niks ◽  
Heather Wilson ◽  
Kajsa G. V. Sigfridsson ◽  
Michael Haumann ◽  
...  
Keyword(s):  
Active Site ◽  
Sulfite Oxidase ◽  
Structure And Function ◽  
And Function ◽  
Human Sulfite Oxidase

scholarly journals Structural Features of a Bacteroidetes-Affiliated Cellulase Linked with a Polysaccharide Utilization Locus

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
A.E. Naas ◽  
A.K. MacKenzie ◽  
B. Dalhus ◽  
V.G.H. Eijsink ◽  
P.B. Pope
Keyword(s):  
Active Site ◽  
Three Dimensional ◽  
Structural Features ◽  
Structure And Function ◽  
Dimensional Structure ◽  
Active Site Cleft ◽  
Polysaccharide Utilization Locus ◽  
And Function ◽  
Rumen Metagenome

Abstract Previous gene-centric analysis of a cow rumen metagenome revealed the first potentially cellulolytic polysaccharide utilization locus, of which the main catalytic enzyme (AC2aCel5A) was identified as a glycoside hydrolase (GH) family 5 endo-cellulase. Here we present the 1.8 Å three-dimensional structure of AC2aCel5A and characterization of its enzymatic activities. The enzyme possesses the archetypical (β/α)8-barrel found throughout the GH5 family and contains the two strictly conserved catalytic glutamates located at the C-terminal ends of β-strands 4 and 7. The enzyme is active on insoluble cellulose and acts exclusively on linear β-(1,4)-linked glucans. Co-crystallization of a catalytically inactive mutant with substrate yielded a 2.4 Å structure showing cellotriose bound in the −3 to −1 subsites. Additional electron density was observed between Trp178 and Trp254, two residues that form a hydrophobic “clamp”, potentially interacting with sugars at the +1 and +2 subsites. The enzyme’s active-site cleft was narrower compared to the closest structural relatives, which in contrast to AC2aCel5A, are also active on xylans, mannans and/or xyloglucans. Interestingly, the structure and function of this enzyme seem adapted to less-substituted substrates such as cellulose, presumably due to the insufficient space to accommodate the side-chains of branched glucans in the active-site cleft.

Metalloenzyme Active-Site Structure and Function through Multifrequency CW and Pulsed ENDOR

1993 ◽  
pp. 151-218 ◽  
Author(s):  
Brian M. Hoffman ◽  
Victoria J. DeRose ◽  
Peter E. Doan ◽  
Ryszard J. Gurbiel ◽  
Andrew L. P. Houseman ◽  
...  
Keyword(s):  
Active Site ◽  
Structure And Function ◽  
Site Structure ◽  
Active Site Structure ◽  
And Function

Insight into the active-site structure and function of cytochrome oxidase by analysis of site-directed mutants of bacterial cytochromeaa 3 and cytochromebo

1993 ◽  
Vol 25 (2) ◽  
pp. 121-136 ◽  
Author(s):  
Jonathan P. Hosler ◽  
Shelagh Ferguson-Miller ◽  
Melissa W. Calhoun ◽  
Jeffrey W. Thomas ◽  
John Hill ◽  
...  
Keyword(s):  
Cytochrome Oxidase ◽  
Active Site ◽  
Structure And Function ◽  
Site Structure ◽  
Active Site Structure ◽  
And Function ◽  
Insight Into

scholarly journals Structure and function of aerotolerant, multiple-turnover THI4 thiazole synthases

2021 ◽  
Author(s):  
Jaya Joshi ◽  
Qiang Li ◽  
Jorge D. Garcia-Garcia ◽  
Bryan J. Leong ◽  
You Hu ◽  
...  
Keyword(s):  
Active Site ◽  
Molecular Basis ◽  
Structure And Function ◽  
Comparative Genomic ◽  
Aerobic Conditions ◽  
Single Turnover ◽  
Metal Cofactor ◽  
Catalytic Metal ◽  
And Function ◽  
Sulfur Donor

Plant and fungal THI4 thiazole synthases produce the thiamin thiazole moiety in aerobic conditions via a single–turnover suicide reaction that uses an active–site Cys residue as sulfur donor. Multiple turnover (i.e. catalytic) THI4s lacking an active–site Cys (non–Cys THI4s) that use sulfide as sulfur donor have been characterized—but only from archaeal methanogens that are anaerobic, O2–sensitivehyperthermophiles from sulfide–rich habitats. These THI4s prefer iron as cofactor. A survey of prokaryote genomes uncovered non–Cys THI4s in aerobic mesophiles from sulfide–poor habitats, suggesting that multiple–turnover THI4 operation is possible in aerobic, mild, low–sulfide conditions. This was confirmed by testing 23 representative non–Cys THI4s for complementation of an Escherichia coli ΔthiG thiazole auxotroph in aerobic conditions. Sixteen were active, and more so when intracellular sulfidelevel was raised by supplying Cys, demonstrating that they function in the presence of O2 at mild temperatures and indicating they use sulfide or a sulfide metabolite as sulfur donor. Comparative genomic evidence linked non–Cys THI4s with proteins from families that bind, transport, or metabolize cobalt or other heavy metals. The crystal structure of the aerotolerant bacterial Thermovibrio ammonificans THI4 was determined to probe the molecular basis of aerotolerance. The structure suggested no large deviations compared to the structures of THI4s from O2–sensitive methanogens but is consistent with an alternative catalytic metal. Together with complementation data, the use of cobalt rather than iron was supported. We conclude that catalytic THI4s can indeed operate aerobically and that the metal cofactor inserted is a likely natural determinant of aerotolerance.

scholarly journals Structure and function of yeast alcohol dehydrogenase

2000 ◽  
Vol 65 (4) ◽  
pp. 207-227 ◽  
Author(s):  
Svetlana Trivic ◽  
Vladimir Leskovac
Keyword(s):  
Alcohol Dehydrogenase ◽  
Substrate Specificity ◽  
Primary Structure ◽  
Active Site ◽  
Hydride Transfer ◽  
Kinetic Mechanism ◽  
Structure And Function ◽  
Chemical Mechanism ◽  
And Function ◽  
Font Color

1. Introduction 2. Isoenzymes of YADH 3. Substrate specificity 4. Kinetic mechanism 5. Primary structure 6. The active site 7. Mutations in the yeast enzyme 8. Chemical mechanism 9. Binding of coenzymes 10. Hydride transfer <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/JSC0008609E">10.2298/JSC0008609E</a><u></b></font>

The importance of the non-active site and non-periodical structure located histidine residue respect to the structure and function of exo-inulinase

2017 ◽  
Vol 98 ◽  
pp. 542-549 ◽  
Author(s):  
Maryam Rezaei Arjomand ◽  
Gholamreza Ahmadian ◽  
Mehran Habibi-Rezaei ◽  
Malihe Hassanzadeh ◽  
Ali Asghar Karkhane ◽  
...  
Keyword(s):  
Active Site ◽  
Structure And Function ◽  
Histidine Residue ◽  
Periodical Structure ◽  
And Function
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