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17 pages, 2157 KiB

Open AccessArticle

Modulation of Kv Channel Gating by Light-Controlled Membrane Thickness

by Rohit Yadav, Juergen Pfeffermann, Nikolaus Goessweiner-Mohr, Toma Glasnov, Sergey A. Akimov and Peter Pohl

Biomolecules 2025, 15(5), 744; https://doi.org/10.3390/biom15050744 - 21 May 2025

Viewed by 702

Abstract

Voltage-gated potassium (Kv) channels are e ssential for shaping action potentials and rely on anionic lipids for proper gating, yet the mechanistic basis of lipid–channel interactions remains unclear. Cryo-electron microscopy studies suggest that, in the down state, arginine residues of the voltage sensor draw lipid phosphates upward, leading to a local membrane thinning of ~5 Å—an effect absent in the open state. To test whether membrane thickness directly affects voltage sensor function, we reconstituted Kv channels from Aeropyrum pernix (KvAP) into planar lipid bilayers containing photoswitchable lipids. Upon blue light illumination, the membrane thickened, and KvAP activity increased; UV light reversed both effects. Our findings indicate that membrane thickening weakens the interaction between lipid phosphates and voltage-sensing arginines in the down state, lowering the energy barrier for the transition to the up state and thereby promoting channel opening. This non-genetic, membrane-mediated approach provides a new strategy to control ion channel activity using light and establishes a direct, reversible link between membrane mechanics and voltage sensing, with potential applications in the remote control of neuronal excitability. Full article

(This article belongs to the Special Issue Light as a Tool to Manipulate the Structure and Function of Membranes and Membrane Proteins)

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17 pages, 2361 KiB

Open AccessArticle

Recombinant Expression of Archaeal Superoxide Dismutases in Plant Cell Cultures: A Sustainable Solution with Potential Application in the Food Industry

by Marta Gogliettino, Stefania Arciello, Fabrizio Cillo, Anna Vittoria Carluccio, Gianna Palmieri, Fabio Apone, Rosa Luisa Ambrosio, Aniello Anastasio, Lorena Gratino, Antonietta Carola and Ennio Cocca

Antioxidants 2022, 11(9), 1731; https://doi.org/10.3390/antiox11091731 - 31 Aug 2022

Cited by 6 | Viewed by 2493

Abstract

Superoxide dismutase (SOD) is a fundamental antioxidant enzyme that neutralises superoxide ions, one of the main reactive oxygen species (ROS). Extremophile organisms possess enzymes that offer high stability and catalytic performances under a wide range of conditions, thus representing an exceptional source of biocatalysts useful for industrial processes. In this study, SODs from the thermo-halophilic Aeropyrum pernix (SOD_Ap) and the thermo-acidophilic Saccharolobus solfataricus (SOD_Ss) were heterologously expressed in transgenic tomato cell cultures. Cell extracts enriched with SOD_Ap and SOD_Ss showed a remarkable resistance to salt and low pHs, respectively, together with optimal activity at high temperatures. Moreover, the treatment of tuna fillets with SOD_Ap-extracts induced an extension of the shelf-life of this product without resorting to the use of illicit substances. The results suggested that the recombinant plant extracts enriched with the extremozymes could find potential applications as dietary supplements in the nutrition sector or as additives in the food preservation area, representing a more natural and appealing alternative to chemical preservatives for the market. Full article

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12 pages, 4698 KiB

Open AccessArticle

RNA Aptamers for a tRNA-Binding Protein from Aeropyrum pernix with Homologous Counterparts Distributed Throughout Evolution

by Senri Ohmori, Marina Wani, Saki Kitabatake, Yuka Nakatsugawa, Tadashi Ando, Takuya Umehara and Koji Tamura

Life 2020, 10(2), 11; https://doi.org/10.3390/life10020011 - 1 Feb 2020

Cited by 4 | Viewed by 3632

Abstract

In the present in vitro selection study, we isolated and characterized RNA aptamers for a tRNA-binding protein (Trbp) from an extremophile archaeon Aeropyrum pernix. Trbp-like structures are frequently found not only in aminoacyl-tRNA synthetases but also in diverse types of proteins from different organisms. They likely arose early in evolution and have played important roles in evolution through interactions with key RNA structures. RNA aptamers specific for A. pernix Trbp were successfully selected from a pool of RNAs composed of 60 nucleotides, including a random 30-nucleotide region. From the secondary structures, we obtained a shortened sequence composed of 21 nucleotides, of which the 3′-terminal single stranded CA nucleotides are essential for binding. This may be related to the initial evolutionary role of the universal CCA-3′ terminus of tRNA in the interaction with Trbp-like structures. Full article

(This article belongs to the Section Proteins and Proteomics)

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8 pages, 1772 KiB

Open AccessArticle

Ultrasound-Assisted Enantioselective Esterification of Ibuprofen Catalyzed by a Flower-Like Nanobioreactor

by Baiyi An, Hailin Fan, Zhuofu Wu, Lu Zheng, Lei Wang, Zhi Wang and Guang Chen

Molecules 2016, 21(5), 565; https://doi.org/10.3390/molecules21050565 - 28 Apr 2016

Cited by 12 | Viewed by 5408

Abstract

A flower-like nanobioreactor was prepared for resolution of ibuprofen in organic solvents. Ultrasound irradiation has been used to improve the enzyme performance of APE1547 (a thermophilic esterase from the archaeon Aeropyrum pernix K1) in the enantioselective esterification. Under optimum reaction conditions (ultrasound power, 225 W; temperature, 45 °C; water activity, 0.21), the immobilized APE1547 showed an excellent catalytic performance (enzyme activity, 13.26 μmol/h/mg; E value, 147.1). After ten repeated reaction batches, the nanobioreactor retained almost 100% of its initial enzyme activity and enantioselectivity. These results indicated that the combination of the immobilization method and ultrasound irradiation can enhance the enzyme performance dramatically. Full article

(This article belongs to the Section Medicinal Chemistry)

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10 pages, 1357 KiB

Open AccessArticle

Bending Elasticity Modulus of Giant Vesicles Composed of Aeropyrum Pernix K1 Archaeal Lipid

by Julia Genova, Nataša Poklar Ulrih, Veronika Kralj-Iglič, Aleš Iglič and Isak Bivas

Life 2015, 5(2), 1101-1110; https://doi.org/10.3390/life5021101 - 26 Mar 2015

Cited by 6 | Viewed by 6875

Abstract

Thermally induced shape fluctuations were used to study elastic properties of giant vesicles composed of archaeal lipids C_25,25-archetidyl (glucosyl) inositol and C_25,25-archetidylinositol isolated from lyophilised Aeropyrum pernix K1 cells. Giant vesicles were created by electroformation in pure water environment. Stroboscopic illumination using a xenon flash lamp was implemented to remove the blur effect due to the finite integration time of the camera and to obtain an instant picture of the fluctuating vesicle shape. The mean weighted value of the bending elasticity modulus k_c of the archaeal membrane determined from the measurements meeting the entire set of qualification criteria was (1.89 ± 0.18) × 10⁻¹⁹ J, which is similar to the values obtained for a membrane composed of the eukaryotic phospholipids SOPC (1.88 ± 0.17) × 10⁻¹⁹ J and POPC (2.00 ± 0.21) ´ 10⁻¹⁹ J. We conclude that membranes composed of archaeal lipids isolated from Aeropyrum pernix K1 cells have similar elastic properties as membranes composed of eukaryotic lipids. This fact, together with the importance of the elastic properties for the normal circulation through blood system, provides further evidence in favor of expectations that archaeal lipids could be appropriate for the design of drug delivery systems. Full article

(This article belongs to the Section Microbiology)

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17 pages, 1467 KiB

Open AccessReview

Experimental Confirmation of a Whole Set of tRNA Molecules in Two Archaeal Species

by Yoh-ichi Watanabe and Yutaka Kawarabayasi

Int. J. Mol. Sci. 2015, 16(1), 2187-2203; https://doi.org/10.3390/ijms16012187 - 20 Jan 2015

Cited by 2 | Viewed by 5861

Abstract

Based on the genomic sequences for most archaeal species, only one tRNA gene (isodecoder) is predicted for each triplet codon. This observation promotes analysis of a whole set of tRNA molecules and actual splicing patterns of interrupted tRNA in one organism. The entire genomic sequences of two Creanarchaeota, Aeropyrum pernix and Sulfolobus tokodaii, were determined approximately 15 years ago. In these genome datasets, 47 and 46 tRNA genes were detected, respectively. Among them, 14 and 24 genes, respectively, were predicted to be interrupted tRNA genes. To confirm the actual transcription of these predicted tRNA genes and identify the actual splicing patterns of the predicted interrupted tRNA molecules, RNA samples were prepared from each archaeal species and used to synthesize cDNA molecules with tRNA sequence-specific primers. Comparison of the nucleotide sequences of cDNA clones representing unspliced and spliced forms of interrupted tRNA molecules indicated that some introns were located at positions other than one base 3' from anticodon region and that bulge-helix-bulge structures were detected around the actual splicing sites in each interrupted tRNA molecule. Whole-set analyses of tRNA molecules revealed that the archaeal tRNA splicing mechanism may be essential for efficient splicing of all tRNAs produced from interrupted tRNA genes in these archaea. Full article

(This article belongs to the Special Issue Functions of Transfer RNAs)

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10 pages, 225 KiB

Open AccessArticle

Enantioselective Esterification of Ibuprofen under Microwave Irradiation

by Zecheng Yang, Xuedun Niu, Xuedong Fang, Ge Chen, Hong Zhang, Hong Yue, Lei Wang, Dantong Zhao and Zhi Wang

Molecules 2013, 18(5), 5472-5481; https://doi.org/10.3390/molecules18055472 - 13 May 2013

Cited by 9 | Viewed by 5752

Abstract

Enantioselective esterification of ibuprofen has been successfully carried out in an organic solvent catalyzed by recombinant APE 1547 (a thermophilic esterase from the archaeon Aeropyrum pernix K1). Here we used microwave irradiation (MW) as the mode of heating to improve the enzyme performance. Under the optimum conditions, the enzyme activity of APE 1547 was 4.16 μmol/mg/h and the enantioselectivity (E value) was 52.9. Compared with conventional heating, the enzyme activity and the enantioselectivity were increased about 21.9-fold and 1.4-fold, respectively. The results also indicated that APE 1547 can maintain 95% of its activity even after being used five times, suggesting that the enzyme is stable under low power MW conditions. Full article

(This article belongs to the Section Organic Chemistry)

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