scholarly journals Tungstoenzymes: Occurrence, Catalytic Diversity and Cofactor Synthesis

Inorganics ◽  
2020 ◽  
Vol 8 (8) ◽  
pp. 44
Author(s):  
Carola S. Seelmann ◽  
Max Willistein ◽  
Johann Heider ◽  
Matthias Boll
Keyword(s):  
Abc Transporter ◽  
Aromatic Compounds ◽  
Metal Binding ◽  
Active Sites ◽  
Structure And Function ◽  
Hydration Reaction ◽  
Dimethyl Sulfoxide Reductase ◽  
Reduction Of Co2 ◽  
And Function ◽  
Electron Transfers

Tungsten is the heaviest element used in biological systems. It occurs in the active sites of several bacterial or archaeal enzymes and is ligated to an organic cofactor (metallopterin or metal binding pterin; MPT) which is referred to as tungsten cofactor (Wco). Wco-containing enzymes are found in the dimethyl sulfoxide reductase (DMSOR) and the aldehyde:ferredoxin oxidoreductase (AOR) families of MPT-containing enzymes. Some depend on Wco, such as aldehyde oxidoreductases (AORs), class II benzoyl-CoA reductases (BCRs) and acetylene hydratases (AHs), whereas others may incorporate either Wco or molybdenum cofactor (Moco), such as formate dehydrogenases, formylmethanofuran dehydrogenases or nitrate reductases. The obligately tungsten-dependent enzymes catalyze rather unusual reactions such as ones with extremely low-potential electron transfers (AOR, BCR) or an unusual hydration reaction (AH). In recent years, insights into the structure and function of many tungstoenzymes have been obtained. Though specific and unspecific ABC transporter uptake systems have been described for tungstate and molybdate, only little is known about further discriminative steps in Moco and Wco biosynthesis. In bacteria producing Moco- and Wco-containing enzymes simultaneously, paralogous isoforms of the metal insertase MoeA may be specifically involved in the molybdenum- and tungsten-insertion into MPT, and in targeting Moco or Wco to their respective apo-enzymes. Wco-containing enzymes are of emerging biotechnological interest for a number of applications such as the biocatalytic reduction of CO2, carboxylic acids and aromatic compounds, or the conversion of acetylene to acetaldehyde.

Biophysical methods toolbox to study ABC exporter structure and function

2017 ◽  
Vol 398 (2) ◽  
pp. 229-235
Author(s):  
Thomas Marcellino ◽  
Vasundara Srinivasan
Keyword(s):  
Membrane Proteins ◽  
Abc Transporter ◽  
Integrated Approach ◽  
Structure And Function ◽  
Dynamic Membrane ◽  
Biophysical Characterization ◽  
Intermediate States ◽  
And Function

Abstract ABC exporters are highly dynamic membrane proteins that span a huge spectrum of different conformations. A detailed integrated approach of cellular, biochemical and biophysical characterization of these ‘open’, ‘closed’ and other intermediate states is central to understanding their function. Almost 40 years after the discovery of the first ABC transporter, thanks to the enormous development in methodologies, a picture is slowly emerging to visualize how these fascinating molecules transport their substrates. This mini review summarizes some of the biophysical tools that have made a major impact in understanding the function of the ABC exporters.

Structural and functional studies of SAV1707 from Staphylococcus aureus elucidate its distinct metal-dependent activity and a crucial residue for catalysis

2021 ◽  
Vol 77 (5) ◽  
pp. 587-598
Author(s):  
Dong-Gyun Kim ◽  
Kyu-Yeon Lee ◽  
Sang Jae Lee ◽  
Seung-Ho Cheon ◽  
Yuri Choi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Metal Binding ◽  
Binding Mode ◽  
Structure And Function ◽  
Functional Study ◽  
Functional Studies ◽  
Dependent Endonuclease ◽  
Metal Selectivity ◽  
Metal Binding Domain ◽  
And Function

The metallo-β-lactamase fold is the most abundant metal-binding domain found in two major kingdoms: bacteria and archaea. Despite the rapid growth in genomic information, most of these enzymes, which may play critical roles in cellular metabolism, remain uncharacterized in terms of structure and function. In this study, X-ray crystal structures of SAV1707, a hypothetical metalloenzyme from Staphylococcus aureus, and its complex with cAMP are reported at high resolutions of 2.05 and 1.55 Å, respectively, with a detailed atomic description. Through a functional study, it was verified that SAV1707 has Ni2+-dependent phosphodiesterase activity and Mn2+-dependent endonuclease activity, revealing a different metal selectivity depending on the reaction. In addition, the crystal structure of cAMP-bound SAV1707 shows a unique snapshot of cAMP that reveals the binding mode of the intermediate, and a key residue Phe511 that forms π–π interactions with cAMP was verified as contributing to substrate recognition by functional studies of its mutant. Overall, these findings characterized the relationship between the structure and function of SAV1707 and may provide further understanding of metalloenzymes possessing the metallo-β-lactamase fold.

Frank William Ernest Gibson 1923 - 2008

2010 ◽  
Vol 21 (1) ◽  
pp. 55 ◽  
Author(s):  
A. J. Pittard ◽  
G. B. Cox
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Genetic Analysis ◽  
Aromatic Compounds ◽  
Aromatic Amino Acids ◽  
Atp Synthesis ◽  
Structure And Function ◽  
Innovative Model ◽  
Distinguished Research ◽  
And Function

Frank Gibson died in Canberra on 11 July 2008. Frank was a highly distinguished research scientist who will be remembered for his pioneering studies in identifying the branch-point compound in the pathway of biosynthesis of a large number of important aromatic compounds followed by a detailed biochemical and genetic analysis of many of the pathways leading to the aromatic amino acids and the so-called aromatic vitamins. Studies on ubiquinone synthesis and function led to an examination of oxidative phosphorylation and the structure and function of the F1F0-ATPase in the bacterium Escherichia coli. This work resulted in the formulation of a highly innovative model, involving rotating subunits of the F0 segment within the membrane and offering an explanation for the mechanism linking proton flow and ATP synthesis.

scholarly journals Local frustration around enzyme active sites

2019 ◽  
Vol 116 (10) ◽  
pp. 4037-4043 ◽  
Author(s):  
Maria I. Freiberger ◽  
A. Brenda Guzovsky ◽  
Peter G. Wolynes ◽  
R. Gonzalo Parra ◽  
Diego U. Ferreiro
Keyword(s):  
Primary Structure ◽  
Active Sites ◽  
Protein Sequences ◽  
Structure And Function ◽  
Energy Landscapes ◽  
Biological Functions ◽  
Complex Energy ◽  
Oligomeric State ◽  
Catalytic Sites ◽  
And Function

Conflicting biological goals often meet in the specification of protein sequences for structure and function. Overall, strong energetic conflicts are minimized in folded native states according to the principle of minimal frustration, so that a sequence can spontaneously fold, but local violations of this principle open up the possibility to encode the complex energy landscapes that are required for active biological functions. We survey the local energetic frustration patterns of all protein enzymes with known structures and experimentally annotated catalytic residues. In agreement with previous hypotheses, the catalytic sites themselves are often highly frustrated regardless of the protein oligomeric state, overall topology, and enzymatic class. At the same time a secondary shell of more weakly frustrated interactions surrounds the catalytic site itself. We evaluate the conservation of these energetic signatures in various family members of major enzyme classes, showing that local frustration is evolutionarily more conserved than the primary structure itself.

Structure and function of aspartate transcarbamoylase studied using chymotrypsin as a probe

1978 ◽  
Vol 56 (6) ◽  
pp. 654-658 ◽  
Author(s):  
William W.-C. Chan ◽  
Caroline A. Enns
Keyword(s):  
Active Sites ◽  
Sodium Dodecyl ◽  
Peptide Bond ◽  
Structure And Function ◽  
Catalytic Subunit ◽  
Native Enzyme ◽  
Aspartate Transcarbamoylase ◽  
Carbamoyl Phosphate ◽  
And Function ◽  
Extended Exposure

Aspartate transcarbamoylase from Escherichia coli is composed of six catalytic (c) and six regulatory (r) polypeptides. We have studied the structure and function of this enzyme using chymotrypsin as a probe. The protease inactivates the isolated catalytic subunit (c3) but has no effects on the native enzyme (c6r6). Under identical conditions, the c3r6 complex is inactivated at a much slower rate than c3. The presence of the substrate analogue succinate together with carbamoyl phosphate reduces substantially the rate of inactivation. Extended exposure to chymotrypsin converts the catalytic subunit into a partially active derivative with a fourfold higher Michaelis constant. This derivative is indistinguishable from the unmodified catalytic subunit in gel electrophoresis under nondenaturing conditions. However, in the presence of sodium dodecyl sulfate, the major fragment in the electropherogram is smaller than that of the intact catalytic polypeptide. The results could be explained by postulating the presence of a chymotrypsin-sensitive peptide bond at or near the active site. Since X-ray crystallographic studies have indicated that the active sites are located in a central cavity, the resistance of the native enzyme towards inactivation may be due to the inability of chymotrypsin to enter this cavity.

scholarly journals Significance of arginine radicals for sturgeon gonadotropin secondary structure and function

2010 ◽  
Vol 64 (3-4) ◽  
pp. 144-148
Author(s):  
Henriks Zenkevičs ◽  
Ilze Vosekalna ◽  
Vija Vose
Keyword(s):  
Secondary Structure ◽  
Active Sites ◽  
Positive Charge ◽  
Cd Spectroscopy ◽  
Structure And Function ◽  
Dimeric Molecule ◽  
Gonadotropic Hormone ◽  
Chemically Modified ◽  
Individual Subunit ◽  
And Function

Significance of arginine radicals for sturgeon gonadotropin secondary structure and function Guanidine groups of arginine side chains were selectively chemically modified with 1,2-cyclohexanedione (CHD) in sturgeon (Acipenser güldenstädti Br.) gonadotropic hormone (GTH) and in its subunits. It was found that only two of the six guanidines were accessible for the reagent and each of the two modified groups was bound to an individual subunit. The results showed that both modified groups were located on the surface of the hormone dimeric molecule. CD-spectroscopy of the modified hormonal preparations did not indicate any considerable changes in their secondary structure. On the basis of the data obtained, a conclusion was made that the free guanidine groups are of exclusive importance for the hormone function at the receptor level as the bearers of the positive charge in the functionally important active sites or effector zones located on the surface of the hormone molecule. Also, it was shown that the guanidine groups played a certain role in sustaining the functionally effective spatial structure of the subunits and GTH.

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