scholarly journals Homology Modeling and Prediction of Catalytic Amino Acid in the Neurotoxin from Indian Cobra (Naja naja)

2008 ◽  
Vol 2 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Pallavi Somvanshi ◽  
Vijai Singh
Keyword(s):  
Amino Acid ◽  
Homology Modeling ◽  
Active Site ◽  
3D Structure ◽  
Nerve Impulse ◽  
Amino Acid Residues ◽  
Small Peptide ◽  
Naja Naja ◽  
Modeling And Prediction ◽  
Catalytic Amino Acid

The neurotoxin secreted by Indian cobra (Naja naja) binds to acetylcholine receptor of nerve cells, which leads to a lump in the nerve impulse, ceases breathing, thereby causing the death of a person due to suffocation. These neurotoxins are small peptide with approximately 7 kDa. Homology modeling was performed to generate the 3D structure of neurotoxins (A, B, C and D) of N. naja, using the known protein template crystal structure (PDB: 2CTX). The validation of 3D structure was done using PROCHECK. Furthermore, the prediction of catalytic amino acid residues in the active site domain of the 3-D structure of neurotoxin was identified. The 3-D structures of neurotoxin and catalytic amino acid residue may be used to target and design the antivenom drugs against the Indian cobra.

The catalytic amino-acid residues in the active site of cellobiohydrolase 1 are involved in chiral recognition

1997 ◽  
Vol 57 (1-3) ◽  
pp. 115-125 ◽  
Author(s):  
Hongbin Henriksson ◽  
Jerry Ståhlberg ◽  
Anu Koivula ◽  
Göran Pettersson ◽  
Christina Divne ◽  
...  
Keyword(s):  
Amino Acid ◽  
Active Site ◽  
Chiral Recognition ◽  
Amino Acid Residues ◽  
Catalytic Amino Acid

scholarly journals Redox Properties of Human Medium-Chain Acyl-CoA Dehydrogenase, Modulation by Charged Active-Site Amino Acid Residues†

Biochemistry ◽  
1998 ◽  
Vol 37 (41) ◽  
pp. 14605-14612 ◽  
Author(s):  
Gina J. Mancini-Samuelson ◽  
Volker Kieweg ◽  
Kim Marie Sabaj ◽  
Sandro Ghisla ◽  
Marian T. Stankovich
Keyword(s):  
Amino Acid ◽  
Active Site ◽  
Redox Properties ◽  
Amino Acid Residues ◽  
Medium Chain ◽  
Chain Acyl

scholarly journals Investigation of major amino acid residues of anti-norfloxacin monoclonal antibodies responsible for binding with fluoroquinolones

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patamalai Boonserm ◽  
Songchan Puthong ◽  
Thanaporn Wichai ◽  
Sajee Noitang ◽  
Pongsak Khunrae ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Amino Acid ◽  
3D Structure ◽  
Cross Reactivity ◽  
Enzyme Linked Immunosorbent Assay ◽  
Amino Acid Residues ◽  
Variable Regions ◽  
Complementarity Determining Regions ◽  
Crucial Part ◽  
Major Amino Acid

AbstractIt is important to understand the amino acid residues that govern the properties of the binding between antibodies and ligands. We studied the binding of two anti-norfloxacins, anti-nor 132 and anti-nor 155, and the fluoroquinolones norfloxacin, enrofloxacin, ciprofloxacin, and ofloxacin. Binding cross-reactivities tested by an indirect competitive enzyme-linked immunosorbent assay indicated that anti-nor 132 (22–100%) had a broader range of cross-reactivity than anti-nor 155 (62–100%). These cross-reactivities correlated with variations in the numbers of interacting amino acid residues and their positions. Molecular docking was employed to investigate the molecular interactions between the fluoroquinolones and the monoclonal antibodies. Homology models of the heavy chain and light chain variable regions of each mAb 3D structure were docked with the fluoroquinolones targeting the crucial part of the complementarity-determining regions. The fluoroquinolone binding site of anti-nor 155 was a region of the HCDR3 and LCDR3 loops in which hydrogen bonds were formed with TYR (H:35), ASN (H:101), LYS (H:106), ASN (L:92), and ASN (L:93). These regions were further away in anti-nor 132 and could not contact the fluoroquinolones. Another binding region consisting of HIS (L:38) and ASP (H:100) was found for norfloxacin, enrofloxacin, and ciprofloxacin, whereas only ASP (H:100) was found for ofloxacin.

scholarly journals How [FeFe]-Hydrogenase Facilitates Bidirectional Proton Transfer

2019 ◽  
Author(s):  
Moritz Senger ◽  
Viktor Eichmann ◽  
Konstantin Laun ◽  
Jifu Duan ◽  
Florian Wittkamp ◽  
...  
Keyword(s):  
Amino Acid ◽  
Proton Transfer ◽  
Active Site ◽  
Molecular Hydrogen ◽  
H2 Production ◽  
Amino Acid Residues ◽  
Difference Spectroscopy ◽  
Dynamic Changes ◽  
In Situ Ir

Hydrogenases are metalloenzymes that catalyse the interconversion of protons and molecular hydrogen, H2. [FeFe]-hydrogenases show particularly high rates of hydrogen turnover and have inspired numerous compounds for biomimetic H2 production. Two decades of research on the active site cofactor of [FeFe]-hydrogenases have put forward multiple models of the catalytic proceedings. In comparison, understanding of the catalytic proton transfer is poor. We were able to identify the amino acid residues forming a proton transfer pathway between active site cofactor and bulk solvent; however, the exact mechanism of catalytic proton transfer remained inconclusive. Here, we employ in situ IR difference spectroscopy on the [FeFe]-hydrogenase from Chlamydomonas reinhardtii evaluating dynamic changes in the hydrogen-bonding network upon catalytic proton transfer. Our analysis allows for a direct, molecular unique assignment to individual amino acid residues. We found that transient protonation changes of arginine and glutamic acid residues facilitate bidirectional proton transfer in [FeFe]-hydrogenases.<br>

scholarly journals The Structural Characterization and Antipathogenic Activities of Quinoin, a Type 1 Ribosome-Inactivating Protein from Quinoa Seeds

2021 ◽  
Vol 22 (16) ◽  
pp. 8964
Author(s):  
Sara Ragucci ◽  
Daniela Bulgari ◽  
Nicola Landi ◽  
Rosita Russo ◽  
Angela Clemente ◽  
...  
Keyword(s):  
Amino Acid ◽  
Homology Modeling ◽  
Peptide Mapping ◽  
Cryphonectria Parasitica ◽  
Tobacco Necrosis Virus ◽  
Amino Acid Residues ◽  
Ribosome Inactivating Protein ◽  
Defensive Role

Quinoin is a type 1 ribosome-inactivating protein (RIP) we previously isolated from the seeds of pseudocereal quinoa (Chenopodium quinoa) and is known as a functional food for its beneficial effects on human health. As the presence of RIPs in edible plants could be potentially risky, here we further characterised biochemically the protein (complete amino acid sequence, homologies/differences with other RIPs and three-dimensional homology modeling) and explored its possible defensive role against pathogens. Quinoin consists of 254 amino acid residues, without cysteinyl residues. As demonstrated by similarities and homology modeling, quinoin preserves the amino acid residues of the active site (Tyr75, Tyr122, Glu177, Arg180, Phe181 and Trp206; quinoin numbering) and the RIP-fold characteristic of RIPs. The polypeptide chain of quinoin contains two N-glycosylation sites at Asn115 and Asp231, the second of which appears to be linked to sugars. Moreover, by comparative MALDI-TOF tryptic peptide mapping, two differently glycosylated forms of quinoin, named pre-quinoin-1 and pre-quinoin-2 (~0.11 mg/100 g and ~0.85 mg/100 g of seeds, respectively) were characterised. Finally, quinoin possesses: (i) strong antiviral activity, both in vitro and in vivo towards Tobacco Necrosis Virus (TNV); (ii) a growth inhibition effect on the bacterial pathogens of plants; and (iii) a slight antifungal effect against two Cryphonectria parasitica strains.

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