Structure and function of the thermostableL-asparaginase fromThermococcus kodakarensis

2017 ◽  
Vol 73 (11) ◽  
pp. 889-895 ◽  
Author(s):  
Jingxu Guo ◽  
Alun R. Coker ◽  
Steve P. Wood ◽  
Jonathan B. Cooper ◽  
Shahid Mahmood Chohan ◽  
...  
Keyword(s):  
Amino Acids ◽  
Food Industry ◽  
Salt Bridge ◽  
Chemotherapeutic Agents ◽  
Type I ◽  
Phosphate Anion ◽  
Closed Conformation ◽  
And Function ◽  
Hydrolysis Of ◽  
Glutaminase Activity

L-Asparaginases catalyse the hydrolysis of asparagine to aspartic acid and ammonia. In addition, L-asparaginase is involved in the biosynthesis of amino acids such as lysine, methionine and threonine. These enzymes have been used as chemotherapeutic agents for the treatment of acute lymphoblastic leukaemia and other haematopoietic malignancies since the tumour cells cannot synthesize sufficient L-asparagine and are thus killed by deprivation of this amino acid. L-Asparaginases are also used in the food industry and have potential in the development of biosensors, for example for asparagine levels in leukaemia. The thermostable type I L-asparaginase fromThermococcus kodakarensis(TkA) is composed of 328 amino acids and forms homodimers in solution, with the highest catalytic activity being observed at pH 9.5 and 85°C. It has aKmvalue of 5.5 mMfor L-asparagine, with no glutaminase activity being observed. The crystal structure of TkA has been determined at 2.18 Å resolution, confirming the presence of two α/β domains connected by a short linker region. The N-terminal domain contains a highly flexible β-hairpin which adopts `open' and `closed' conformations in different subunits of the solved TkA structure. In previously solved L-asparaginase structures this β-hairpin was only visible when in the `closed' conformation, whilst it is characterized with good electron density in all of the subunits of the TkA structure. A phosphate anion resides at the active site, which is formed by residues from both of the neighbouring monomers in the dimer. The high thermostability of TkA is attributed to the high arginine and salt-bridge content when compared with related mesophilic enzymes.

TBC Proteins: Miraculous Regulators of Rabs GTPase Molecular Switches

2021 ◽  
Author(s):  
Jun Yan ◽  
Yingcheng Zheng ◽  
Song Han ◽  
Jun Yin ◽  
Yinping Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Intracellular Transport ◽  
Molecular Switches ◽  
Small Gtpases ◽  
Structure And Function ◽  
Rab Gtpase ◽  
Cellular Functions ◽  
Eukaryotic Proteins ◽  
And Function ◽  
Hydrolysis Of

TBC proteins are classified as a group because they contain a common conserved structure TBC domain. TBC domain consists of approximately 200 amino acids and presents in many eukaryotic proteins. It is reported that TBC proteins have been shown to function as a GAP for Rab GTPase. TBC proteins catalyze the hydrolysis of GTP and promote the conversion of Rab-GTP to Rab-GDP, thus participating in the specific intracellular transport. Many TBC proteins play important roles in cellular functions in mammals, and their deletions or mutations are closely related to many diseases. It is important to systematically sort out these findings and functions of the TBC family and illuminate the significance of TBC proteins in different physiological conditions. Here we reviewed the structure and function of TBC proteins, especially the function related to to Rab small GTPases.

scholarly journals Structure-based alignment of human caspase recruitment domains provides a framework for understanding their function

2016 ◽  
Author(s):  
Joseph P. Boyle ◽  
Tom Monie
Keyword(s):  
Protein Interactions ◽  
Salt Bridge ◽  
Type I ◽  
Hydrophobic Core ◽  
Death Domain ◽  
Protein Protein Interactions ◽  
Sequence Alignments ◽  
And Function ◽  
Human Caspase ◽  
Death Domain Superfamily

AbstractIntracellular signalling is driven by protein-protein interactions. Members of the Death Domain superfamily mediate protein-protein interactions in both cell death and innate immune signalling pathways. They drive the formation of macromolecular complexes that act as a scaffold for protein recruitment and downstream signal transduction. Death Domain family members have low sequence identity, complicating their identification and predictions of their structure and function. We have taken all known human caspase recruitment domains (CARDs), a subfamily of the Death Domain superfamily, and generated a structure-guided sequence alignment. This alignment has enabled the identification of 14 positions that define the hydrophobic core and present a template for the identification of novel CARD sequences. We identify a conserved salt bridge in over half of all human CARDs and find a subset of CARDs likely to be regulated by tyrosine phosphorylation in their type I interface. Our alignment highlights that the CARDs of NLRC3 and NLRC5 are likely to be pseudodomains that have lost some of their original functionality. Together these studies demonstrate the benefits of structure-guided sequence alignments in understanding protein functionality.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

Type I Interferons promote maintenance and function of follicular T helper cells in vitro

2019 ◽  
Author(s):  
S Ehrlich ◽  
K Wild ◽  
M Smits ◽  
K Zoldan ◽  
M Hofmann ◽  
...  
Keyword(s):  
T Helper Cells ◽  
Type I Interferons ◽  
Type I ◽  
T Helper ◽  
Helper Cells ◽  
Follicular T Helper Cells ◽  
And Function

Deinking of recycled paper by coupling of the enzyme endo-β-1,4-D-glucanasa and the cellulose, and by using a laboratory flotation column

MRS Advances ◽  
2020 ◽  
Vol 5 (52-53) ◽  
pp. 2669-2678
Author(s):  
Jeovani González P. ◽  
Ramiro Escudero G
Keyword(s):  
Amino Acids ◽  
Sodium Hydroxide ◽  
Paper Industry ◽  
Computational Simulation ◽  
Cellulose Fibers ◽  
Residual Water ◽  
Chemical Reagent ◽  
Recycled Paper ◽  
Flotation Column ◽  
Hydrolysis Of

AbstractDeinking of recycled office (MOW) paper was carried out by using a flotation column and adding separately sodium hydroxide, and the enzyme Cellulase Thricodema Sp., as defibrillators.The de-inked cellulose fibers were characterized according to the standards of the paper industry, to compare the efficiency of the deinking of each chemical reagent used to hydrolyze the fibers and defibrillate them.The computational simulation of the molecular coupling between the enzyme and cellulose was performed, to establish the enzyme-cellulose molecular complex and then to identify the principal amino-acids of endo-β-1,4-D-glucanase in this molecular link, which are responsible for the hydrolysis of the cellulose.Experimental results show the feasibility to replace sodium hydroxide with the enzyme Cellulase Thricodema Sp., by obtaining deinked cellulose with similar optical and physical properties.The use of the enzyme instead of sodium hydroxide avoids the contamination of the residual water; in addition to that, the column is operated more easily, taking into consideration that the pH of the system goes from alkaline to neutral.

Plasma and skeletal muscle free amino acids in type I, insulin-treated diabetic subjects

Diabetes ◽  
1985 ◽  
Vol 34 (8) ◽  
pp. 812-815 ◽  
Author(s):  
L. Borghi ◽  
R. Lugari ◽  
A. Montanari ◽  
P. Dall'Argine ◽  
G. F. Elia ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Amino Acids ◽  
Free Amino Acids ◽  
Free Amino ◽  
Type I

Studies on Chromatographic Fractioning by Cations Exchangers of a Bovine Hemoglobin Hydrolysate

2018 ◽  
Vol 69 (10) ◽  
pp. 2794-2798
Author(s):  
Alina Diana Panainte ◽  
Ionela Daniela Morariu ◽  
Nela Bibire ◽  
Madalina Vieriu ◽  
Gladiola Tantaru ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Retention Time ◽  
Chromatographic Separation ◽  
Bovine Hemoglobin ◽  
Reverse Phase ◽  
Hplc System ◽  
Fast Flow ◽  
Hydrolysis Of ◽  
Phase Column

A peptidic hydrolysate has been obtained through hydrolysis of bovine hemoglobin using pepsin. The fractioning of the hydrolysate was performed on a column packed with CM-Sepharose Fast Flow. The hydrolysate and each fraction was filtered and then injected into a HPLC system equipped with a Vydak C4 reverse phase column (0.46 x 25 cm), suitable for the chromatographic separation of large peptides with 20 to 30 amino acids. The detection was done using mass spectrometry, and the retention time, size and distribution of the peptides were determined.

Collagen-the Ultrastructural Element of the Bone Matrix

2018 ◽  
Vol 69 (7) ◽  
pp. 1706-1709
Author(s):  
Nicoleta Dumitru ◽  
Andra Cocolos ◽  
Andra Caragheorgheopol ◽  
Constantin Dumitrache ◽  
Ovidiu Gabriel Bratu ◽  
...  
Keyword(s):  
Type I Collagen ◽  
Bone Microarchitecture ◽  
Complex Structure ◽  
Bone Matrix ◽  
Organic Matrix ◽  
Bone Diseases ◽  
Bone Collagen ◽  
Type I ◽  
New Therapeutic Approaches ◽  
And Function

There is an increased interest and more studies highlight the fact that bone strength depends not only on bone tissue quantity, but also on its quality, which is characterized by the geometry and shape of bones, trabecular bone microarchitecture, mineral content, organic matrix and bone turnover. Fibrillar type I collagen is the major organic component of bone matrix, providing form and a stable template for mineralization. The biomedical importance of collagen as a biomaterial for medical and cosmetic purposes and the improvement of the molecular, cellular biology and analytical technologies, led to increasing interest in establishing the structure of this protein and in setting of the relationships between sequence, structure, and function. Bone collagen crosslinking chemistry and its molecular packing structure are considered to be distinct features. This unique post-translational modifications provide to the fibrillar collagen matrices properties such as tensile strength and viscoelasticity. Understanding the complex structure of bone type I collagen as well as the dynamic nature of bone tissues will help to manage new therapeutic approaches to bone diseases.

Insights into Potent Therapeutical Antileukemic Agent L-glutaminase Enzyme Under Solid-state Fermentation: A Review

2020 ◽  
Vol 21 (3) ◽  
pp. 211-220 ◽  
Author(s):  
Chandrasai Potla Durthi ◽  
Madhuri Pola ◽  
Satish Babu Rajulapati ◽  
Anand Kishore Kola
Keyword(s):  
Solid State ◽  
Solid State Fermentation ◽  
Food Industry ◽  
Energy Requirement ◽  
Production Studies ◽  
Wide Range ◽  
Hybridoma Technology ◽  
Bacteria And Fungi ◽  
The Stability ◽  
Glutaminase Activity

Aim & objective: To review the applications and production studies of reported antileukemic drug L-glutaminase under Solid-state Fermentation (SSF). Overview: An amidohydrolase that gained economic importance because of its wide range of applications in the pharmaceutical industry, as well as the food industry, is L-glutaminase. The medical applications utilized it as an anti-tumor agent as well as an antiretroviral agent. L-glutaminase is employed in the food industry as an acrylamide degradation agent, as a flavor enhancer and for the synthesis of theanine. Another application includes its use in hybridoma technology as a biosensing agent. Because of its diverse applications, scientists are now focusing on enhancing the production and optimization of L-glutaminase from various sources by both Solid-state Fermentation (SSF) and submerged fermentation studies. Of both types of fermentation processes, SSF has gained importance because of its minimal cost and energy requirement. L-glutaminase can be produced by SSF from both bacteria and fungi. Single-factor studies, as well as multi-level optimization studies, were employed to enhance L-glutaminase production. It was concluded that L-glutaminase activity achieved by SSF was 1690 U/g using wheat bran and Bengal gram husk by applying feed-forward artificial neural network and genetic algorithm. The highest L-glutaminase activity achieved under SSF was 3300 U/gds from Bacillus sp., by mixture design. Purification and kinetics studies were also reported to find the molecular weight as well as the stability of L-glutaminase. Conclusion: The current review is focused on the production of L-glutaminase by SSF from both bacteria and fungi. It was concluded from reported literature that optimization studies enhanced L-glutaminase production. Researchers have also confirmed antileukemic and anti-tumor properties of the purified L-glutaminase on various cell lines.

scholarly journals Green extraction of proteins, umami and other free amino acids from brown macroalgae Ascophyllum nodosum and Fucus vesiculosus

2021 ◽  
Author(s):  
Viruja Ummat ◽  
Marco Garcia-Vaquero ◽  
Mahesha M. Poojary ◽  
Marianne N. Lund ◽  
Colm O’Donnell ◽  
...  
Keyword(s):  
Amino Acids ◽  
Citric Acid ◽  
Free Amino Acids ◽  
Free Amino ◽  
Food Industry ◽  
Ascophyllum Nodosum ◽  
Fucus Vesiculosus ◽  
Green Solvents ◽  
Brown Macroalgae ◽  
Extraction Solvent

AbstractSeaweeds are a valuable potential source of protein, as well as free amino acids (FAAs) with umami flavour which are in high demand by the food industry. The most commonly used flavouring agents in the food industry are chemically synthesised and therefore are subject to concerns regarding their safety and associated consumer resistance. This study focuses on the effects of extraction time (1 and 2 h) and solvents (0.1 M HCl, 1% citric acid and deionised water) on the extraction of protein and FAAs including umami FAAs from Irish brown seaweeds (Ascophyllum nodosum and Fucus vesiculosus). Extraction yields were influenced by both the extraction solvent and time, and also varied according to the seaweed used. Both seaweeds investigated were found to be good sources of protein, FAAs including umami FAAs, demonstrating potential application as flavouring agents in the food industry. Overall, the use of green solvents (deionised water and citric acid) resulted in higher recoveries of compounds compared to HCl. The results of this study will facilitate the use of more sustainable solvents in industry for the extraction of proteins and flavouring agents from seaweed.

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