scholarly journals Structure-based engineering of substrate specificity for pinoresinol-lariciresinol reductases

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ying Xiao ◽  
Kai Shao ◽  
Jingwen Zhou ◽  
Lian Wang ◽  
Xueqi Ma ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Bound States ◽  
Large Scale ◽  
Structural Diversity ◽  
Structural Elements ◽  
Isatis Indigotica ◽  
Substrate Specificities ◽  
Lignan Biosynthesis ◽  
Insight Into

AbstractPinoresinol–lariciresinol reductases (PLRs) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols, and this represents the entry point for the synthesis of 8-8′ lignans and contributes greatly to their structural diversity. Of particular interest has been the determination of how differing substrate specificities are achieved with these enzymes. Here, we present crystal structures of IiPLR1 from Isatis indigotica and pinoresinol reductases (PrRs) AtPrR1 and AtPrR2 from Arabidopsis thaliana, in the apo, substrate-bound and product-bound states. Each structure contains a head-to-tail homodimer, and the catalytic pocket comprises structural elements from both monomers. β4 loop covers the top of the pocket, and residue 98 from the loop governs catalytic specificity. The substrate specificities of IiPLR1 and AtPrR2 can be switched via structure-guided mutagenesis. Our study provides insight into the molecular mechanism underlying the substrate specificity of PLRs/PrRs and suggests an efficient strategy for the large-scale commercial production of the pharmaceutically valuable compound lariciresinol.

scholarly journals Structure based engineering for substrate specificity of pinoresinol-lariciresinol reductases

2020 ◽  
Author(s):  
Ying Xiao ◽  
Kai Shao ◽  
Jingwen Zhou ◽  
Lian Wang ◽  
Di Wu ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Molecular Mechanism ◽  
Large Scale ◽  
Structural Diversity ◽  
Commercial Production ◽  
Structural Elements ◽  
Substrate Specificities ◽  
Lignan Biosynthesis ◽  
Binding Forms ◽  
Insight Into

Abstract Pinoresinol–lariciresinol reductases (PLR) are enzymes involved in the lignan biosynthesis after the initial dimerization of two monolignols, which represents the entry point for the synthesis of 8-8′ lignans and contributes greatly to their structural diversity. Of particular interest has been in determining how differing substrate specificities are achieved with these enzymes. Here, we present crystal structures of IiPLR1/AtPrR1/AtPrR2 in the apo, substrate-binding and product-binding forms. Each structure contains a head-to-tail homodimer, and the catalytic pocket comprises structural elements from both monomers. A loop β4 covers the top of the pocket, and residue 98 from the loop governs catalytic specificity. Structure-guided mutagenesis could switch the substrate specificity of IiPLR1 and AtPrR2, respectively. Our study provides new insight into the molecular mechanism underlying the substrate specificity of PLR/PrRs and suggests an efficient strategy for the large-scale commercial production of the pharmaceutically valuable compound lariciresinol.

scholarly journals Structural and evolutionary relationships of “AT-less” type I polyketide synthase ketosynthases

2015 ◽  
Vol 112 (41) ◽  
pp. 12693-12698 ◽  
Author(s):  
Jeremy R. Lohman ◽  
Ming Ma ◽  
Jerzy Osipiuk ◽  
Boguslaw Nocek ◽  
Youngchang Kim ◽  
...  
Keyword(s):  
Amino Acid ◽  
Substrate Specificity ◽  
Polyketide Synthase ◽  
Acyl Carrier Protein ◽  
Structural Diversity ◽  
Type I ◽  
Substrate Specificities ◽  
In Trans ◽  
Canonical Type ◽  
Insight Into

Acyltransferase (AT)-less type I polyketide synthases (PKSs) break the type I PKS paradigm. They lack the integrated AT domains within their modules and instead use a discrete AT that acts in trans, whereas a type I PKS module minimally contains AT, acyl carrier protein (ACP), and ketosynthase (KS) domains. Structures of canonical type I PKS KS-AT didomains reveal structured linkers that connect the two domains. AT-less type I PKS KSs have remnants of these linkers, which have been hypothesized to be AT docking domains. Natural products produced by AT-less type I PKSs are very complex because of an increased representation of unique modifying domains. AT-less type I PKS KSs possess substrate specificity and fall into phylogenetic clades that correlate with their substrates, whereas canonical type I PKS KSs are monophyletic. We have solved crystal structures of seven AT-less type I PKS KS domains that represent various sequence clusters, revealing insight into the large structural and subtle amino acid residue differences that lead to unique active site topologies and substrate specificities. One set of structures represents a larger group of KS domains from both canonical and AT-less type I PKSs that accept amino acid-containing substrates. One structure has a partial AT-domain, revealing the structural consequences of a type I PKS KS evolving into an AT-less type I PKS KS. These structures highlight the structural diversity within the AT-less type I PKS KS family, and most important, provide a unique opportunity to study the molecular evolution of substrate specificity within the type I PKSs.

scholarly journals Structural insight into DNA joining: from conserved mechanisms to diverse scaffolds

2020 ◽  
Vol 48 (15) ◽  
pp. 8225-8242 ◽  
Author(s):  
Adele Williamson ◽  
Hanna-Kirsti S Leiros
Keyword(s):  
Bound States ◽  
Treatment Options ◽  
Structural Diversity ◽  
Dna Ligase ◽  
Dna Ligases ◽  
Enzymatic Mechanism ◽  
Technological Potential ◽  
Multifunctional Enzymes ◽  
New Treatment ◽  
Insight Into

Abstract DNA ligases are diverse enzymes with essential functions in replication and repair of DNA; here we review recent advances in their structure and distribution and discuss how this contributes to understanding their biological roles and technological potential. Recent high-resolution crystal structures of DNA ligases from different organisms, including DNA-bound states and reaction intermediates, have provided considerable insight into their enzymatic mechanism and substrate interactions. All cellular organisms possess at least one DNA ligase, but many species encode multiple forms some of which are modular multifunctional enzymes. New experimental evidence for participation of DNA ligases in pathways with additional DNA modifying enzymes is defining their participation in non-redundant repair processes enabling elucidation of their biological functions. Coupled with identification of a wealth of DNA ligase sequences through genomic data, our increased appreciation of the structural diversity and phylogenetic distribution of DNA ligases has the potential to uncover new biotechnological tools and provide new treatment options for bacterial pathogens.

scholarly journals Sequence and Structural Analysis of AA9 and AA10 LPMOs: An Insight into the Basis of Substrate Specificity and Regioselectivity

2019 ◽  
Vol 20 (18) ◽  
pp. 4594 ◽  
Author(s):  
Xiaoli Zhou ◽  
Xiaohua Qi ◽  
Hongxia Huang ◽  
Honghui Zhu
Keyword(s):  
Structural Analysis ◽  
Substrate Specificity ◽  
Molecular Basis ◽  
Substrate Binding ◽  
Binding Modes ◽  
Substrate Specificities ◽  
Lytic Polysaccharide Monooxygenases ◽  
Polysaccharide Monooxygenases ◽  
Natural Carbon ◽  
Insight Into

Lytic polysaccharide monooxygenases (LPMOs) are key enzymes in both the natural carbon cycle and the biorefinery industry. Understanding the molecular basis of LPMOs acting on polysaccharide substrates is helpful for improving industrial cellulase cocktails. Here we analyzed the sequences, structures, and substrate binding modes of LPMOs to uncover the factors that influence substrate specificity and regioselectivity. Our results showed that the different compositions of a motif located on L2 affect the electrostatic potentials of substrate binding surfaces, which in turn affect substrate specificities of AA10 LPMOs. A conserved Asn at a distance of 7 Å from the active center Cu might, together with the conserved Ser immediately before the second catalytic His, determine the localization of LPMOs on substrate, and thus contribute to C4-oxidizing regioselectivity. The findings in this work provide an insight into the molecular basis of substrate specificity and regioselectivity of LPMOs.

Large-scale Motion of Solar Filaments

2000 ◽  
Vol 179 ◽  
pp. 205-208
Author(s):  
Pavel Ambrož ◽  
Alfred Schroll
Keyword(s):  
Magnetic Flux ◽  
Proper Motion ◽  
Time Scale ◽  
Large Scale ◽  
Accuracy Of Measurements ◽  
Solar Filaments ◽  
General Movement ◽  
Scale Motion ◽  
Velocity Scatter

AbstractPrecise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

Methods for the Quantification of Salivary Cortisol and of a-amylase in Biosensors and Portable Devices

2018 ◽  
Vol 68 (12) ◽  
pp. 2857-2859
Author(s):  
Cristina Mihaela Ghiciuc ◽  
Andreea Silvana Szalontay ◽  
Luminita Radulescu ◽  
Sebastian Cozma ◽  
Catalina Elena Lupusoru ◽  
...  
Keyword(s):  
Real Time ◽  
Medical Practice ◽  
Salivary Cortisol ◽  
Clinical Studies ◽  
Large Scale ◽  
Psychological Research ◽  
Portable Devices ◽  
Salivary Amylase ◽  
Specificity And Sensitivity

There is an increasing interest in the analysis of salivary biomarkers for medical practice. The objective of this article was to identify the specificity and sensitivity of quantification methods used in biosensors or portable devices for the determination of salivary cortisol and salivary a-amylase. There are no biosensors and portable devices for salivary amylase and cortisol that are used on a large scale in clinical studies. These devices would be useful in assessing more real-time psychological research in the future.

Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform

2019 ◽  
Vol 22 (5) ◽  
pp. 346-354
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Large Scale ◽  
Underlying Mechanism ◽  
Luciferase Assay ◽  
Reporter System ◽  
E Coli ◽  
Starting Point ◽  
High Concentrations ◽  
Mic Value

Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

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