The role of cationic amino acid residues in the lethal activity of stonustoxin from stonefish (Synanceja horridat) venom

In the present study, we determined the functional role of 15 positively charged amino acid residues at or within 1 of the predicted 11 transmembrane helixes of the flounder renal sodium-dicarboxylate cotransporter fNaDC-3. Using site-directed mutagenesis, histidine (H), lysine (K), and arginine (R) residues of fNaDC-3 were replaced by alanine (A), isoleucine (I), or leucine (L). Most mutants showed sodium-dependent, lithium-inhibitable [14C]succinate uptake and, in two-electrode voltage-clamp (TEVC) experiments, Km and Δ Imax values comparable to wild-type (WT) fNaDC-3. The replacement of R109 and R110 by alanine and isoleucine (RR109/110AI) prevented the expression of fNaDC-3 at the plasma membrane. When the lysines at positions 232 and 235 were replaced by isoleucine (KK232/235II), the transporter was expressed but showed small transport rates and succinate-induced currents. K114I, located within transmembrane helix 4, showed [14C]succinate uptake similar to WT but relatively small inward currents. When K114 was replaced by arginine, glutamic acid (E), or glutamine (Q), all mutants were expressed at the cell surface. In [14C]succinate uptake and TEVC experiments performed simultaneously on the same oocytes, uptake was similar to or higher than WT, whereas succinate-induced currents were either comparable (K114R) to, or considerably smaller (K114E, K114I, K114Q) than, those evoked by WT. These results suggest that a positively charged residue at position 114 is required for electrogenic sodium-dicarboxylate cotransport.

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The arrangement and role of some of the amino acid residues in the beta-ketoacyl synthetase site of chicken liver fatty acid synthetase.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)44201-3 ◽

1983 ◽

Vol 258 (20) ◽

pp. 12482-12486

Author(s):

J K Stoops ◽

S J Henry ◽

S J Wakil

Keyword(s):

Fatty Acid ◽

Amino Acid ◽

Fatty Acid Synthetase ◽

Chicken Liver ◽

Amino Acid Residues ◽

Liver Fatty Acid

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Rational design of novel amphipathic antimicrobial peptides focused on the distribution of cationic amino acid residues

MedChemComm ◽

10.1039/c9md00166b ◽

2019 ◽

Vol 10 (6) ◽

pp. 896-900 ◽

Cited By ~ 5

Author(s):

Takashi Misawa ◽

Chihiro Goto ◽

Norihito Shibata ◽

Motoharu Hirano ◽

Yutaka Kikuchi ◽

...

Keyword(s):

Antimicrobial Activity ◽

Amino Acid ◽

Human Cell ◽

Hemolytic Activity ◽

Rational Design ◽

Cell Cytotoxicity ◽

Amino Acid Residues ◽

High Antimicrobial Activity ◽

Cationic Amino Acid ◽

Helical Peptide

Amphipathic helical peptideStripeshowed high antimicrobial activity, low hemolytic activity, and low human cell cytotoxicity.

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Chemical Modification of Lysozyme, Glucose 6-Phosphate Dehydrogenase, and Bovine Eye Lens Proteins Induced by Peroxyl Radicals: Role of Oxidizable Amino Acid Residues

Chemical Research in Toxicology ◽

10.1021/tx300372t ◽

2013 ◽

Vol 26 (1) ◽

pp. 67-77 ◽

Cited By ~ 28

Author(s):

Andrea Arenas ◽

Camilo López-Alarcón ◽

Marcelo Kogan ◽

Eduardo Lissi ◽

Michael J. Davies ◽

...

Keyword(s):

Amino Acid ◽

Chemical Modification ◽

Peroxyl Radicals ◽

Eye Lens ◽

Amino Acid Residues ◽

Lens Proteins ◽

Glucose 6 Phosphate Dehydrogenase ◽

Eye Lens Proteins

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Deletion of the Actin-Associated Tropomyosin Tpm3 Leads to Reduced Cell Complexity in Cultured Hippocampal Neurons—New Insights into the Role of the C-Terminal Region of Tpm3.1

Cells ◽

10.3390/cells10030715 ◽

2021 ◽

Vol 10 (3) ◽

pp. 715

Author(s):

Tamara Tomanić ◽

Claire Martin ◽

Holly Stefen ◽

Esmeralda Parić ◽

Peter Gunning ◽

...

Keyword(s):

Amino Acid ◽

Hippocampal Neurons ◽

Molecular Mechanisms ◽

Growth Cones ◽

Amino Acid Residues ◽

Terminal Amino Acid ◽

C Terminus ◽

Primary Mouse ◽

Terminal Amino

Tropomyosins (Tpms) have been described as master regulators of actin, with Tpm3 products shown to be involved in early developmental processes, and the Tpm3 isoform Tpm3.1 controlling changes in the size of neuronal growth cones and neurite growth. Here, we used primary mouse hippocampal neurons of C57/Bl6 wild type and Bl6Tpm3flox transgenic mice to carry out morphometric analyses in response to the absence of Tpm3 products, as well as to investigate the effect of C-terminal truncation on the ability of Tpm3.1 to modulate neuronal morphogenesis. We found that the knock-out of Tpm3 leads to decreased neurite length and complexity, and that the deletion of two amino acid residues at the C-terminus of Tpm3.1 leads to more detrimental changes in neurite morphology than the deletion of six amino acid residues. We also found that Tpm3.1 that lacks the 6 C-terminal amino acid residues does not associate with stress fibres, does not segregate to the tips of neurites, and does not impact the amount of the filamentous actin pool at the axonal growth cones, as opposed to Tpm3.1, which lacks the two C-terminal amino acid residues. Our study provides further insight into the role of both Tpm3 products and the C-terminus of Tpm3.1, and it forms the basis for future studies that aim to identify the molecular mechanisms underlying Tpm3.1 targeting to different subcellular compartments.

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Role of amino acid residues at the interface of α52asparginyl-N-glycosyl chain of human choriogonadotropin

Molecular and Cellular Endocrinology ◽

10.1016/s0303-7207(99)00026-x ◽

1999 ◽

Vol 150 (1-2) ◽

pp. 47-56 ◽

Cited By ~ 1

Author(s):

Kui Shao ◽

Sathyamangalam V. Balasubramanian ◽

Om P. Bahl

Keyword(s):

Amino Acid ◽

Amino Acid Residues ◽

Human Choriogonadotropin

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Circular RNA NF1-419 Inhibits Proliferation and Induces Apoptosis by Regulating Lipid Metabolism in Astroglioma Cells

Recent Patents on Anti-Cancer Drug Discovery ◽

10.2174/1574892816666210729125802 ◽

2021 ◽

Vol 16 ◽

Author(s):

Ran Li ◽

Xiaocui Tang ◽

Changqiong Xu ◽

Yinrui Guo ◽

Longkai Qi ◽

...

Keyword(s):

Lipid Metabolism ◽

Amino Acid ◽

Tumor Growth ◽

Ganoderma Lucidum ◽

Amino Acid Transporter ◽

Cationic Amino Acid Transporter ◽

Cationic Amino Acid ◽

Acid Transporter ◽

Astroglioma Cells

Background: Astroglioma is the most common primary tumor of the central nervous system. Currently, there is no effective treatment for astroglioma. In the present study, the extract (L3) from Ganoderma Lucidum (G.lucidum) was found to inhibit the growth of astroglioma U87 cells and change the expression of circular RNAs (circRNAs). One of these, including the circular NF1-419 (circNF1-419), was of interest because NF1 gene is a classic tumor suppressor gene. Objective: The functional role of circ-NF1-419 in the inhibition of astroglioma cells remains unknown. This study focuses on the role of circNF1-419 in functional abnormalities of U87 astroglioma cells and aims to elaborate on its regulatory mechanism. Methods: The circNF1-419 overexpressing U87 (U87-NF1-419) cells were constructed. We generated U87-NF1-419 to evaluate the role of circNF1-419 on cell cycle, apoptosis, proliferation, tumor growth and metabolic regulation. Finally, we used docking screening to identify compounds in G. lucidum extracts that target circ-419. Results: U87-NF1-419 can promote cell apoptosis and regulate lipid metabolism through glycerophospholipid metabolism and retrograde endocannabinoid signaling. Further examinations revealed that the expression of metabolic regulators, such as L-type voltage-operated calcium channels (L-VOCC), phospholipase C-β3 (PLCβ3), Mucin1, cationic amino acid transporter 4 (CAT4), cationic amino acid transporter 1 (CAT1) and a kinase (PRKA) anchor protein 4 (AKAP4) was inhibited, while phosphatidylserine synthase 1 (PTDSS1) was enhanced in U87-NF1-419 cells. In vivo experiments showed that circNF1-419 inhibits tumor growth in BALB/C nude mice, and enhanced AKAP4 and PTDSS1 in tumor tissues. The virtual docking screening results supported that ganosporeric acid A, ganodermatriol, ganoderic acid B and α-D-Arabinofuranosyladenine in L3 could activate circNF1-419 in astroglioma treatment. Conclusion: This study indicated that circNF1-419 could be a therapeutic target for the clinical treatment of astroglioma. L3 from Ganoderma Lucidum (G.lucidum) could inhibit astroglioma growth by activating circNF1-419.

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The functional dyad of scorpion toxin Pi1 is not itself a prerequisite for toxin binding to the voltage-gated Kv1.2 potassium channels

Biochemical Journal ◽

10.1042/bj20030115 ◽

2004 ◽

Vol 377 (1) ◽

pp. 25-36 ◽

Cited By ~ 50

Author(s):

Stéphanie MOUHAT ◽

Amor MOSBAH ◽

Violeta VISAN ◽

Heike WULFF ◽

Muriel DELEPIERRE ◽

...

Keyword(s):

Amino Acid ◽

Scorpion Toxin ◽

Xenopus Laevis Oocytes ◽

Amino Acid Residues ◽

Voltage Gated ◽

Toxin Binding ◽

Ic50 Values

Pi1 is a 35-residue scorpion toxin cross-linked by four disulphide bridges that acts potently on both small-conductance Ca2+-activated (SK) and voltage-gated (Kv) K+ channel subtypes. Two approaches were used to investigate the relative contribution of the Pi1 functional dyad (Tyr-33 and Lys-24) to the toxin action: (i) the chemical synthesis of a [A24,A33]-Pi1 analogue, lacking the functional dyad, and (ii) the production of a Pi1 analogue that is phosphorylated on Tyr-33 (P-Pi1). According to molecular modelling, this phosphorylation is expected to selectively impact the two amino acid residues belonging to the functional dyad without altering the nature and three-dimensional positioning of other residues. P-Pi1 was directly produced by peptide synthesis to rule out any possibility of trace contamination by the unphosphorylated product. Both Pi1 analogues were compared with synthetic Pi1 for bioactivity. In vivo, [A24,A33]-Pi1 and P-Pi1 are lethal by intracerebroventricular injection in mice (LD50 values of 100 and 40 µg/mouse, respectively). In vitro, [A24,A33]-Pi1 and P-Pi1 compete with 125I-apamin for binding to SK channels of rat brain synaptosomes (IC50 values of 30 and 10 nM, respectively) and block rat voltage-gated Kv1.2 channels expressed in Xenopus laevis oocytes (IC50 values of 22 µM and 75 nM, respectively), whereas they are inactive on Kv1.1 or Kv1.3 channels at micromolar concentrations. Therefore, although both analogues are less active than Pi1 both in vivo and in vitro, the integrity of the Pi1 functional dyad does not appear to be a prerequisite for the recognition and binding of the toxin to the Kv1.2 channels, thereby highlighting the crucial role of other toxin residues with regard to Pi1 action on these channels. The computed simulations detailing the docking of Pi1 peptides on to the Kv1.2 channels support an unexpected key role of specific basic amino acid residues, which form a basic ring (Arg-5, Arg-12, Arg-28 and Lys-31 residues), in toxin binding.

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