Computational and functional analysis of β-lactam resistance in Zymomonas mobilis

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Sheik Sheik Abdul Kader ◽  
Mahalakshmi Ayyasamy ◽  
Rajnish Narayanan ◽  
Sridhar Jayavel ◽  
Gunasekaran Paramasamy
Keyword(s):  
Substrate Specificity ◽  
Zymomonas Mobilis ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Docking Studies ◽  
Pcr Analysis ◽  
Resistance Determinants ◽  
Disk Diffusion Assay ◽  
Aliphatic Index ◽  
High Concentrations

AbstractZymomonas mobilis, a Gram-negative ethanologenic non-pathogenic bacterium, is reported to exhibit resistance to high concentrations of β-lactam antibiotics. In the present study, Z. mobilis was found to be resistant to I-IV generations of cephalosporins and carbapenems, i.e. narrow, broad and extended spectrum β-lactam antibiotics. We have analysed the genome of Z. mobilis (GenBank accession No.: NC 006526) harbouring multiple genes coding for β-lactamases (BLA), β-lactamase domain containing proteins (BDP) and penicillin binding proteins (PBP). The conserved domain database analysis of BDPs predicted them to be members of metallo β-lactamase superfamily. Further, class C specific multidomain AmpC (β-lactamase C) was found in the three β-lactamases. The β-lactam resistance determinants motifs, HXHXD, KXG, SXXK, SXN, and YXN are present in the BLAs, BDPs and PBPs of Z. mobilis. The predicted theoretical pI and aliphatic index values suggested their stability. One of the PBPs, PBP2, was predicted to share functional association with rod shape determining proteins (GenBank accession Nos. YP_162095 and YP_162091). Homology modelling of three dimensional structures of the β-lactam resistance determinants and further docking studies with penicillin and other β-lactam antibiotics indicated their substrate-specificity. Semi-quantitative PCR analysis indicated that the expression of all BLAs and one BDP are induced by penicillin. Disk diffusion assay, SDS-PAGE and zymogram analysis confirms the substrate specificity of the β-lactam resistance determinants. This study gives a broader picture of the β-lactam resistance determinants of a non-pathogenic ethanologenic Z. mobilis bacterium that could have implications in laboratories since it is routinely used in many research laboratories in the world for ethanol, fructooligosaccharides, levan production and has also been reported to be present in wine and beer as a spoilage organism.

scholarly journals Determinants of specificity for aflatoxin B1-8,9-epoxide in Alpha-class glutathione S-transferases

1999 ◽  
Vol 339 (1) ◽  
pp. 95-101 ◽  
Author(s):  
Paul D. McDONAGH ◽  
David J. JUDAH ◽  
John D. HAYES ◽  
Lu-Yun LIAN ◽  
Gordon E. NEAL ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Substrate Specificity ◽  
High Activity ◽  
Aflatoxin B1 ◽  
Active Site ◽  
Homology Modelling ◽  
Three Dimensional ◽  
Glutathione S Transferase ◽  
Glutathione S Transferases ◽  
Aspartate Residue

We have used homology modelling, based on the crystal structure of the human glutathione S-transferase (GST) A1-1, to obtain the three-dimensional structures of rat GSTA3 and rat GSTA5 subunits bound to S-aflatoxinyl–glutathione. The resulting models highlight two residues, at positions 208 and 108, that could be important for determining, either directly or indirectly, substrate specificity for aflatoxin-exo-8,9-epoxide among the Alpha-class GSTs. Residues at these positions were mutated in human GSTA1-1 (Met-208, Leu-108), rat GSTA3-3 (Glu-208, His-108) and rat GSTA5-5 (Asp-208, Tyr-108): in the active rat GSTA5-5 to those in the inactive GSTA1-1; and in the inactive human GSTA1-1 and rat GSTA3-3 to those in the active rat GSTA5-5. These studies show clearly that, in all three GSTs, an aspartate residue at position 208 is a prerequisite for high activity in aflatoxin-exo-8,9-epoxide conjugation, although this alone is not sufficient; other residues in the vicinity, particularly residues 103–112, are important, perhaps for the optimal orientation of the aflatoxin-exo-8,9-epoxide in the active site for catalysis to occur.

scholarly journals In silico binding analysis of human CD40 ligand mimetic molecule, 3-(dimethylamino)-1-phenyl-1-propanone hydrochloride (3-DPH), with CD40 receptor molecules of various mammalian species

2021 ◽  
Vol 42 (2) ◽  
pp. 186-191
Author(s):  
S. Sivagami ◽  
◽  
R. Rathna ◽  
S. Nagavignesh ◽  
N.V. Ghone ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Homo Sapiens ◽  
Homology Modelling ◽  
Mammalian Species ◽  
Three Dimensional ◽  
Cd40 Ligand ◽  
Docking Studies ◽  
Ligand Complex ◽  
Papio Anubis ◽  
Key Words 3

Aim: To investigate the binding of human CD40 ligand (CD40L) mimetic molecule, 3-(dimethylamino)-1-phenyl-1-propanone hydrochloride (3-DPH), with CD40 receptor (CD40R) molecules of Homo sapiens, Cavia porcellus, Cricetulus griseus, Macaca mulatta, Mus musculus, Oryctolagus cuniculus, Papio anubis and Rattus norvegicus species using bioinformatics tool. Methodology: Three-dimensional structures of CD40Rs and CD40Ls for various mammalian species were generated using the published crystal structure of human CD40 receptor-ligand complex by homology modelling using SWISS-MODEL tool. Furthermore, human CD40L mimetic molecule, 3-DPH was docked against the generated CD40R of various mammalian species using AUTODOCK 4.2. Results: Docking studies revealed that documented HIS78 and GLN79 residues of human CD40R were the key interaction residues, which interacted with human CD40L and 3-DPH. The CD40Rs of H. sapiens, C. porcellus, C. griseus, M. mulatta, M. musculus, O. cuniculus, P. anubis, and R. norvegicus bind with 3-DPH with a binding energy -4.67, -5.22, -5.19, -4.62, -4.85, -4.63, -4.51, and -4.86 kcal/mol, respectively. Interpretation: Molecular docking studies provide crucial insight into the binding affinity and interaction of 3-DPH at the active site of CD40R of the respective mammalian species. O. cuniculus and M. musculus species were found to be appropriate animal models for further evaluation of the therapeutic effect of human CD40L mimetic molecule Key words: 3-DPH, Animal model, CD40R, CD40L, Homo sapeins, Molecular docking

Towards further Understanding the Structural Requirements of Combretastatin- like Chalcones as Inhibitors of Microtubule Polymerization

2020 ◽  
Vol 16 (2) ◽  
pp. 155-166
Author(s):  
Naveen Dhingra ◽  
Anand Kar ◽  
Rajesh Sharma
Keyword(s):  
Three Dimensional ◽  
3D Qsar ◽  
Docking Study ◽  
Structure Activity Relationship ◽  
Docking Studies ◽  
Activity Relationship ◽  
Structural Requirement ◽  
Ligand Interaction ◽  
Microtubule Polymerization ◽  
Structure Activity

Background: Microtubules are dynamic filamentous cytoskeletal structures which play several key roles in cell proliferation and trafficking. They are supposed to contribute in the development of important therapeutic targeting tumor cells. Chalcones are important group of natural compounds abundantly found in fruits & vegetables that are known to possess anticancer activity. We have used QSAR and docking studies to understand the structural requirement of chalcones for understanding the mechanism of microtubule polymerization inhibition. Methods: Three dimensional (3D) QSAR (CoMFA and CoMSIA), pharmacophore mapping and molecular docking studies were performed for the generation of structure activity relationship of combretastatin-like chalcones through statistical models and contour maps. Results: Structure activity relationship revealed that substitution of electrostatic, steric and donor groups may enhance the biological activity of compounds as inhibitors of microtubule polymerization. From the docking study, it was clear that compounds bind at the active site of tubulin protein. Conclusion: The given strategies of modelling could be an encouraging way for designing more potent compounds as well as for the elucidation of protein-ligand interaction.

scholarly journals Structural and functional insights into esterase-mediated macrolide resistance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Michał Zieliński ◽  
Jaeok Park ◽  
Barry Sleno ◽  
Albert M. Berghuis
Keyword(s):  
Active Site ◽  
Pathogenic Bacteria ◽  
Catalytic Mechanism ◽  
Three Dimensional ◽  
Resistance Mechanisms ◽  
Docking Studies ◽  
Macrolide Resistance ◽  
Flexible Docking ◽  
Sequence Identity ◽  
Substrate Spectrum

AbstractMacrolides are a class of antibiotics widely used in both medicine and agriculture. Unsurprisingly, as a consequence of their exensive usage a plethora of resistance mechanisms have been encountered in pathogenic bacteria. One of these resistance mechanisms entails the enzymatic cleavage of the macrolides’ macrolactone ring by erythromycin esterases (Eres). The most frequently identified Ere enzyme is EreA, which confers resistance to the majority of clinically used macrolides. Despite the role Eres play in macrolide resistance, research into this family enzymes has been sparse. Here, we report the first three-dimensional structures of an erythromycin esterase, EreC. EreC is an extremely close homologue of EreA, displaying more than 90% sequence identity. Two structures of this enzyme, in conjunction with in silico flexible docking studies and previously reported mutagenesis data allowed for the proposal of a detailed catalytic mechanism for the Ere family of enzymes, labeling them as metal-independent hydrolases. Also presented are substrate spectrum assays for different members of the Ere family. The results from these assays together with an examination of residue conservation for the macrolide binding site in Eres, suggests two distinct active site archetypes within the Ere enzyme family.

Characterization of an A-type cyclin-dependent kinase gene from Dendrobium candidum

Biologia ◽  
2012 ◽  
Vol 67 (2) ◽  
Author(s):  
Gang Zhang ◽  
Chao Song ◽  
Ming-Ming Zhao ◽  
Biao Li ◽  
Shun-Xing Guo
Keyword(s):  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Postembryonic Development ◽  
Kinase Domain ◽  
Dimensional Structure ◽  
Pcr Analysis ◽  
Kinase Gene ◽  
Multiple Sequence ◽  
Dendrobium Candidum ◽  
Rapid Amplification

AbstractCyclin-dependent kinases (CDKs) play an essential role in cell cycle regulation during the embryonic and postembryonic development of organisms. To better understand the molecular mechanisms of CDKs involved in embryogenesis regulation in the endangered medicinal plant Dendrobium candidum Wall. ex Lindl., a 1229-bp full-length cDNA of an A-type CDK gene, Denca;CDKA;1, was identified using 3′ rapid amplification of cDNA end (RACE) PCR. Denca;CDKA;1 was predicted to encode a 294 amino acid residue-long protein of 33.76 kDa with an isoelectric point of 7.72. The deduced Denca;CDKA;1 protein contained a conserved serine/threonine-protein kinase domain (S-TKc) and a canonical cyclinbinding “PSTAIRE” motif. Multiple sequence alignment indicated that members of CDKA family from various plants exhibited a high degree of sequence identity ranging from 82% to 93%. A neighbor-joining phylogenetic tree showed that Denca;CDKA;1 was clustered into the plant group and was distant from the animal and fungal groups. The modeled three-dimensional structure of Denca;CDKA;1 exhibited the similar functional structure of a fold consisting of β-sheets and α-helices joined by discontinuous random coils forming two relatively independent lobes. Quantitative real-time PCR analysis revealed that Denca;CDKA;1 transcripts were the most abundant in protocorm-like bodies with 4.76 fold, followed by that in roots (4.19 fold), seeds (2.57 fold), and stems (1.57 fold). This study characterized the novel Denca;CDKA;1 gene from D. candidum for the first time and the results will be useful for further functional determination of the gene.

Design of Dual COX-2 and 5-LOX Inhibitors with Iron-Chelating Properties Using Structure-Based and Ligand-Based Methods

2021 ◽  
Vol 18 ◽  
Author(s):  
Jelena Bošković ◽  
Dušan Ružić ◽  
Olivera Čudina ◽  
Katarina Nikolic ◽  
Vladimir Dobričić
Keyword(s):  
Molecular Docking ◽  
External Validation ◽  
Three Dimensional ◽  
3D Qsar ◽  
Quantitative Structure Activity Relationship ◽  
Docking Studies ◽  
Qsar Analysis ◽  
In Silico Admet ◽  
Cox 2 ◽  
Lox Inhibitors

Background: Inflammation is common pathogenesis of many diseases progression, such as malignancy, cardiovascular and rheumatic diseases. The inhibition of the synthesis of inflammatory mediators by modulation of cyclooxygenase (COX) and lipoxygenase (LOX) pathways provides a challenging strategy for the development of more effective drugs. Objective: The aim of this study was to design dual COX-2 and 5-LOX inhibitors with iron-chelating properties using a combination of ligand-based (three-dimensional quantitative structure-activity relationship (3D-QSAR)) and structure-based (molecular docking) methods. Methods: The 3D-QSAR analysis was applied on a literature dataset consisting of 28 dual COX-2 and 5-LOX inhibitors in Pentacle software. The quality of developed COX-2 and 5-LOX 3D-QSAR models were evaluated by internal and external validation methods. The molecular docking analysis was performed in GOLD software, while selected ADMET properties were predicted in ADMET predictor software. Results: According to the molecular docking studies, the class of sulfohydroxamic acid analogues, previously designed by 3D-QSAR, was clustered as potential dual COX-2 and 5-LOX inhibitors with iron-chelating properties. Based on the 3D-QSAR and molecular docking, 1j, 1g, and 1l were selected as the most promising dual COX-2 and 5-LOX inhibitors. According to the in silico ADMET predictions, all compounds had an ADMET_Risk score less than 7 and a CYP_Risk score lower than 2.5. Designed compounds were not estimated as hERG inhibitors, and 1j had improved intrinsic solubility (8.704) in comparison to the dataset compounds (0.411-7.946). Conclusion: By combining 3D-QSAR and molecular docking, three compounds (1j, 1g, and 1l) are selected as the most promising designed dual COX-2 and 5-LOX inhibitors, for which good activity, as well as favourable ADMET properties and toxicity, are expected.

Erratum to: A seed coat cyanohydrin glucosyltransferase is associated with bitterness in almond (Prunus dulcis) kernels

2008 ◽  
Vol 35 (4) ◽  
pp. 346 ◽  
Author(s):  
Tricia K. Franks ◽  
Abbas Yadollahi ◽  
Michelle G. Wirthensohn ◽  
Jennifer R. Guerin ◽  
Brent N. Kaiser ◽  
...  
Keyword(s):  
Transcriptional Regulation ◽  
Secondary Metabolite ◽  
Polyclonal Antibody ◽  
Seed Coat ◽  
Control Point ◽  
Prunus Dulcis ◽  
Pcr Analysis ◽  
Prunus Amygdalus ◽  
High Concentrations ◽  
Important Site

The secondary metabolite amygdalin is a cyanogenic diglucoside that at high concentrations is associated with intense bitterness in seeds of the Rosaceae, including kernels of almond (Prunus dulcis (Mill.), syn. Prunus amygdalus D. A. Webb Batsch). Amygdalin is a glucoside of prunasin, itself a glucoside of R-mandelonitrile (a cyanohydrin). Here we report the isolation of an almond enzyme (UGT85A19) that stereo-selectively glucosylates R-mandelonitrile to produce prunasin. In a survey of developing kernels from seven bitter and 11 non-bitter genotypes with polyclonal antibody raised to UGT85A19, the enzyme was found to accumulate to higher levels in the bitter types in later development. This differential accumulation of UGT85A19 is associated with more than three-fold greater mandelonitrile glucosyltransferase activity in bitter kernels compared with non-bitter types, and transcriptional regulation was demonstrated using quantitative-PCR analysis. UGT85A19 and its encoding transcript were most concentrated in the testa (seed coat) of the kernel compared with the embryo, and prunasin and amygdalin were differentially compartmentalised in these tissues. Prunasin was confined to the testa and amygdalin was confined to the embryo. These results are consistent with the seed coat being an important site of synthesis of prunasin as a precursor of amygdalin accumulation in the kernel. The presence of UGT85A19 in the kernel and other tissues of both bitter and non-bitter types indicates that its expression is unlikely to be a control point for amygdalin accumulation and suggests additional roles for the enzyme in almond metabolism.

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