scholarly journals Functional Characterization of an Anthocyanin Dimalonyltransferase in Maize

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 2020
Author(s):  
Michael Paulsmeyer ◽  
John Juvik
Keyword(s):  
Substrate Specificity ◽  
Structure Function ◽  
Functional Characterization ◽  
Malonyl Coa ◽  
Natural Colorants ◽  
Acylated Anthocyanins ◽  
The Stability ◽  
Kinetics Of ◽  
Insight Into

Anthocyanins are pigments with appealing hues that are currently being used as sources of natural colorants. The interaction of acylation on the stability of anthocyanin molecules has long been known. Maize is an abundant source of malonylglucoside and dimalonylglucoside anthocyanins. The enzyme Aat1 is an anthocyanin acyltransferase known to synthesize the majority of acylated anthocyanins in maize. In this paper, we characterize the substrate specificity and reaction kinetics of Aat1. It was found that Aat1 has anthocyanin 3-O-glucoside dimalonyltransferase activity and is only the second enzyme of this type characterized to this date. Our results indicate that Aat1 can utilize malonyl-CoA; succinyl-CoA and every anthocyanin 3-O-glucoside tested. Results of this study provide insight into the structure–function relations of dimalonyltransferases and give a unique insight into the activity of monocot anthocyanin acyltransferases.

scholarly journals Probing the promiscuity of ent-kaurene oxidases via combinatorial biosynthesis

2016 ◽  
Vol 113 (9) ◽  
pp. 2526-2531 ◽  
Author(s):  
Sibongile Mafu ◽  
Meirong Jia ◽  
Jiachen Zi ◽  
Dana Morrone ◽  
Yisheng Wu ◽  
...  
Keyword(s):  
Natural Products ◽  
Metabolic Engineering ◽  
Substrate Specificity ◽  
Plant Hormone ◽  
Structural Similarity ◽  
Combinatorial Biosynthesis ◽  
Underlying Structure ◽  
Engineering System ◽  
Insight Into

The substrate specificity of enzymes from natural products’ metabolism is a topic of considerable interest, with potential biotechnological use implicit in the discovery of promiscuous enzymes. However, such studies are often limited by the availability of substrates and authentic standards for identification of the resulting products. Here, a modular metabolic engineering system is used in a combinatorial biosynthetic approach toward alleviating this restriction. In particular, for studies of the multiply reactive cytochrome P450, ent-kaurene oxidase (KO), which is involved in production of the diterpenoid plant hormone gibberellin. Many, but not all, plants make a variety of related diterpenes, whose structural similarity to ent-kaurene makes them potential substrates for KO. Use of combinatorial biosynthesis enabled analysis of more than 20 such potential substrates, as well as structural characterization of 12 resulting unknown products, providing some insight into the underlying structure–function relationships. These results highlight the utility of this approach for investigating the substrate specificity of enzymes from complex natural products’ biosynthesis.

scholarly journals Characterization of the Global Stabilizing Substitution A77V and Its Role in the Evolution of CTX-M β-Lactamases

2015 ◽  
Vol 59 (11) ◽  
pp. 6741-6748 ◽  
Author(s):  
Meha P. Patel ◽  
Bartlomiej G. Fryszczyn ◽  
Timothy Palzkill
Keyword(s):  
Antibiotic Resistance ◽  
Adaptive Mutation ◽  
Common Mechanism ◽  
Antibiotic Hydrolysis ◽  
The Stability ◽  
Kinetics Of ◽  
M 14

ABSTRACTThe widespread use of oxyimino-cephalosporin antibiotics drives the evolution of the CTX-M family of β-lactamases that hydrolyze these drugs and confer antibiotic resistance. Clinically isolated CTX-M enzymes carrying the P167S or D240G active site-associated adaptive mutation have a broadened substrate profile that includes the oxyimino-cephalosporin antibiotic ceftazidime. The D240G substitution is known to reduce the stability of CTX-M-14 β-lactamase, and the P167S substitution is shown here to also destabilize the enzyme. Proteins are marginally stable entities, and second-site mutations that stabilize the enzyme can offset a loss in stability caused by mutations that enhance enzyme activity. Therefore, the evolution of antibiotic resistance enzymes can be dependent on the acquisition of stabilizing mutations. The A77V substitution is present in CTX-M extended-spectrum β-lactamases (ESBLs) from a number of clinical isolates, suggesting that it may be important in the evolution of antibiotic resistance in this family of β-lactamases. In this study, the effects of the A77V substitution in the CTX-M-14 model enzyme were characterized with regard to the kinetic parameters for antibiotic hydrolysis as well as enzyme expression levelsin vivoand protein stabilityin vitro. The A77V substitution has little effect on the kinetics of oxyimino-cephalosporin hydrolysis, but it stabilizes the CTX-M enzyme and compensates for the loss of stability resulting from the P167S and D240G mutations. The acquisition of global stabilizing mutations, such as A77V, is an important feature in β-lactamase evolution and a common mechanism in protein evolution.

scholarly journals Structural and functional characterization of mouse U7 small nuclear RNA active in 3' processing of histone pre-mRNA.

1988 ◽  
Vol 8 (4) ◽  
pp. 1518-1524 ◽  
Author(s):  
D Soldati ◽  
D Schümperli
Keyword(s):  
Sea Urchin ◽  
Functional Characterization ◽  
Rnase H ◽  
Primer Extension ◽  
Small Nuclear Rna ◽  
Nuclear Rna ◽  
Processing Signal ◽  
Insight Into

Oligonucleotides derived from the spacer element of the histone RNA 3' processing signal were used to characterize mouse U7 small nuclear RNA (snRNA), i.e., the snRNA component active in 3' processing of histone pre-mRNA. Under RNase H conditions, such oligonucleotides inhibited the processing reaction, indicating the formation of a DNA-RNA hybrid with a functional ribonucleoprotein component. Moreover, these oligonucleotides hybridized to a single nuclear RNA species of approximately 65 nucleotides. The sequence of this RNA was determined by primer extension experiments and was found to bear several structural similarities with sea urchin U7 snRNA. The comparison of mouse and sea urchin U7 snRNA structures yields some further insight into the mechanism of histone RNA 3' processing.

Phylogenetic analysis of fungal aquaporins provides insight into their possible role in water transport of mycorrhizal associations

Botany ◽  
2013 ◽  
Vol 91 (8) ◽  
pp. 495-504 ◽  
Author(s):  
Hao Xu ◽  
Janice E.K. Cooke ◽  
Janusz J. Zwiazek
Keyword(s):  
Water Transport ◽  
Mycorrhizal Fungi ◽  
Functional Characterization ◽  
Arbuscular Mycorrhizal ◽  
Gene Families ◽  
Fungal Species ◽  
Comparative Genomic ◽  
Mycorrhizal Associations ◽  
Insight Into

In mycorrhizal associations, water transport properties of the fungal hyphae may have a profound effect on water transport of the host plant. The importance of aquaporins, water-transporting members of the major intrinsic protein (MIP) family, in facilitating water transport has been widely acknowledged and extensively studied in plants. However, until recently, relatively little was known about the structure, function, and regulation of fungal MIPs. The rapid increase in the number of sequenced fungal genomes, including Laccaria bicolor and other mycorrhizal fungi, has enabled functional and comparative genomic investigations to delineate the role that fungal MIPs play in mycorrhizal-facilitated plant water transport. Phylogenic analysis of 229 fungal MIPs from 88 species revealed that MIPs of mycorrhizal fungal species fall into four clusters delineated by functionally characterized fungal MIPs: the orthodox aquaporins, the aquaglyceroporins, the facultative fungal aquaporins, and the X intrinsic proteins. This comparative genomics analysis, together with in silico structural characterization of predicted MIPs and recently published functional characterization of MIPs from a small number of ectomycorrhizal and arbuscular mycorrhizal species, provide new insight into MIP gene families of mycorrhizal fungi and possible roles for fungal aquaporins in water relations of mycorrhizal plant–fungus symbioses.

scholarly journals Discovery and characterization of Hv1-type proton channels in reef-building corals.

2021 ◽  
Author(s):  
Gisela Rangel-Tescas ◽  
Cecilia Cervantes ◽  
Miguel A Cervantes-Rocha ◽  
Esteban Suarez-Delgado ◽  
Anastazia T Banaszak ◽  
...  
Keyword(s):  
Voltage Dependence ◽  
Ph Regulation ◽  
Functional Characterization ◽  
Gene Encoding ◽  
Proton Channels ◽  
Gating Model ◽  
Mechanistic Insight ◽  
Voltage Dependent ◽  
Insight Into

Voltage-dependent proton-permeable channels are membrane proteins mediating a number of important physiological functions. Here we report the presence of a gene encoding for Hv1 voltage-dependent, proton-permeable channels in two species of reef-building corals. We performed a characterization of their biophysical properties and found that these channels are fast-activating and modulated by the pH gradient in a manner that makes them interesting models for studying these processes more easily. We have also developed an allosteric gating model that provides mechanistic insight into the modulation of voltage-dependence by protons. This work also represents the first functional characterization of any ion channel in scleractinian corals. We discuss the implications of the presence of these channels in the membranes of coral cells in the calcification and pH regulation processes and possible consequences of ocean acidification related to the function of these channels.

Urine Proteomics Profiling and Functional Characterization of Knee Osteoarthritis Using iTRAQ Technology

2019 ◽  
Vol 51 (11) ◽  
pp. 735-740 ◽  
Author(s):  
Ke Xiao ◽  
Lingjia Yu ◽  
Lisi Zhu ◽  
Zhihong Wu ◽  
Xisheng Weng ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Joint Function ◽  
Urine Protein ◽  
Western Blots ◽  
Urine Proteomics ◽  
Protein Levels ◽  
Mass Spectrometry Technology ◽  
Proteome Profile ◽  
Insight Into

AbstractOsteoarthritis (OA) is a degenerative chronic disease affecting the whole joint structures. With the increment in life expectancy and aging population, OA has become one of the largest socioeconomic burdens, associated with pain and loss of joint function. However, early laboratory tests of OA are still lacking. Therefore, new diagnostic tests for this disease are urgently needed. In this study, to gain an insight into the pathogenesis and the potential biomarkers of OA, we implemented a comparative urine proteomics study on OA patients and health people using iTRAQ-based mass spectrometry technology. Western blotting was used to validate the relative changes in urine protein levels for four of the identified proteins. We constructed a comprehensive urine proteome profile of the OA patients and identified 102 proteins differently changed in abundance. Forty-six proteins were upregulated and 56 proteins were significantly downregulated in OA patients. Furthermore, the proteins, COL-4, MMP9, adiponectin, and BBOX1 were validated through Western blots, which can serve as valuable candidate biomarkers and help to illustrate the pathogenesis of OA. These findings may provide clues for promising biomarkers for the early diagnosis and also offer a theoretical basis for the early treatment of OA.

scholarly journals Functional characterization of tlmH in Streptoalloteichus hindustanus E465-94 ATCC 31158 unveiling new insight into tallysomycinbiosynthesis and affording a novel bleomycin analog

2010 ◽  
Vol 6 (2) ◽  
pp. 349-356 ◽  
Author(s):  
Meifeng Tao ◽  
Liyan Wang ◽  
Evelyn Wendt-Pienkowski ◽  
Ningning Zhang ◽  
Dong Yang ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Insight Into

scholarly journals The Role of Hydraulic Hysteresis on the Hydrological Response of Pyroclastic Silty Covers

Water ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 628 ◽  
Author(s):  
Guido Rianna ◽  
Luca Comegna ◽  
Luca Pagano ◽  
Luciano Picarelli ◽  
Alfredo Reder
Keyword(s):  
Slope Failure ◽  
Hysteretic Behavior ◽  
Recent Experience ◽  
Hydrological Response ◽  
Hydraulic Hysteresis ◽  
The Stability ◽  
Hydrological Effects ◽  
Insight Into

A significant part of the recent geotechnical literature concerning pyroclastic soils is focused on the characterization of the hydrological effects of precipitations and their implications for the stability conditions of unsaturated sloping covers. Recent experience shows that suction-induced strength reduction is influenced by various factors including hydraulic hysteresis. A deeper insight into the hysteretic water retention behavior of these materials and its effects upon their response to dry/wetting conditions is a major goal of this paper, which exploits the data provided by the monitoring of a volcanic ash. Based on the parameters retrieved from data calibration, the hydrological response of a virtual slope subject to one-dimensional rainfall infiltration is investigated by numerical analyses and compared with the results obtained through the usually adopted non-hysteretic approaches. The analysis demonstrates that considering the hysteretic behavior may be crucial for a proper evaluation of the conditions leading to slope failure.

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