scholarly journals The role of aromatic residues in the hydrophobic core of the villin headpiece subdomain

2009 ◽  
Vol 11 (3) ◽  
pp. 680-687 ◽  
Author(s):  
Benjamin S. Frank ◽  
Didem Vardar ◽  
Deirdre A. Buckley ◽  
C. James McKnight
Keyword(s):  
Hydrophobic Core ◽  
Villin Headpiece ◽  
Aromatic Residues

scholarly journals Molecular Dynamics of Chloroplast Membranes Isolated from Wild-Type Barley and a Brassinosteroid-Deficient Mutant Acclimated to Low and High Temperatures

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Iwona Sadura ◽  
Dariusz Latowski ◽  
Jana Oklestkova ◽  
Damian Gruszka ◽  
Marek Chyc ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Temperature Stress ◽  
High Temperatures ◽  
Biological Membrane ◽  
Hydrophobic Core ◽  
Wild Type ◽  
Chloroplast Membranes ◽  
Paramagnetic Resonance ◽  
Photosynthetic Membranes

Plants have developed various acclimation strategies in order to counteract the negative effects of abiotic stresses (including temperature stress), and biological membranes are important elements in these strategies. Brassinosteroids (BR) are plant steroid hormones that regulate plant growth and development and modulate their reaction against many environmental stresses including temperature stress, but their role in modifying the properties of the biological membrane is poorly known. In this paper, we characterise the molecular dynamics of chloroplast membranes that had been isolated from wild-type and a BR-deficient barley mutant that had been acclimated to low and high temperatures in order to enrich the knowledge about the role of BR as regulators of the dynamics of the photosynthetic membranes. The molecular dynamics of the membranes was investigated using electron paramagnetic resonance (EPR) spectroscopy in both a hydrophilic and hydrophobic area of the membranes. The content of BR was determined, and other important membrane components that affect their molecular dynamics such as chlorophylls, carotenoids and fatty acids in these membranes were also determined. The chloroplast membranes of the BR-mutant had a higher degree of rigidification than the membranes of the wild type. In the hydrophilic area, the most visible differences were observed in plants that had been grown at 20 °C, whereas in the hydrophobic core, they were visible at both 20 and 5 °C. There were no differences in the molecular dynamics of the studied membranes in the chloroplast membranes that had been isolated from plants that had been grown at 27 °C. The role of BR in regulating the molecular dynamics of the photosynthetic membranes will be discussed against the background of an analysis of the photosynthetic pigments and fatty acid composition in the chloroplasts.

Core Role of Hydrophobic Core of Polymeric Nanomicelle in Endosomal Escape of siRNA

Nano Letters ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 3680-3689
Author(s):  
Chunhui Li ◽  
Junhui Zhou ◽  
Yidi Wu ◽  
Yanliang Dong ◽  
Lili Du ◽  
...  
Keyword(s):  
Endosomal Escape ◽  
Hydrophobic Core ◽  
Core Role

Role of aromatic residues in the structure-function relationship of .alpha.-bungarotoxin

Biochemistry ◽  
1982 ◽  
Vol 21 (11) ◽  
pp. 2592-2600 ◽  
Author(s):  
Yee Hsiung Chen ◽  
Jang Chyi Tai ◽  
Wan Jen Huang ◽  
Ming Zong Lai ◽  
Mien Chie Hung ◽  
...  
Keyword(s):  
Structure Function ◽  
Aromatic Residues ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Alpha Bungarotoxin ◽  
Relationship Of

The role of conserved non-aromatic residues in the Lactobacillus amylovorus α-amylase CBM26-starch interaction

2019 ◽  
Vol 121 ◽  
pp. 829-838 ◽  
Author(s):  
Silvia Armenta ◽  
Zaira Sánchez-Cuapio ◽  
Maria Elena Munguia ◽  
Nancy O. Pulido ◽  
Amelia Farrés ◽  
...  
Keyword(s):  
Aromatic Residues ◽  
Lactobacillus Amylovorus

scholarly journals Free Energy Landscape and Rate Estimation of the Aromatic Ring Flips in Basic Pancreatic Trypsin Inhibitor Using Metadynamics

2021 ◽  
Author(s):  
Pär Söderhjelm ◽  
Mandar Kulkarni
Keyword(s):  
Free Energy ◽  
Trypsin Inhibitor ◽  
Side Chain ◽  
Side Chains ◽  
Aromatic Residues ◽  
Basic Pancreatic Trypsin Inhibitor ◽  
Pancreatic Trypsin Inhibitor ◽  
Energy Surfaces ◽  
Aromatic Side Chains

Aromatic side-chains (phenylalanine and tyrosine) of a protein flip by 180° around the Cβ-Cγ axis (χ2 dihedral of side-chain) producing two symmetry-equivalent states. The ring-flip dynamics act as an NMR probe to understand local conformational fluctuations. Ring-flips are categorized as slow (ms onwards) or fast (ns to near ms) based on timescales accessible to NMR experiments. In this study, we investigated the ability of the infrequent metadynamics approach to discriminate between slow and fast ring-flips for eight individual aromatic side-chains (F4, Y10, Y21, F22, Y23, F33, Y35, F45) of basic pancreatic trypsin inhibitor (BPTI). Well-tempered metadynamics simulations were performed to observe ring-flipping free energy surfaces for all eight aromatic residues. The results indicate that χ2 as a standalone collective variable (CV) is not sufficient to classify fast and slow ring-flips. Most of the residues needed χ1 (N−Cχα) as a complementary CV, indicating the importance of librational motions in ring-flips. Multiple pathways and mechanisms were observed for residues F4, Y10, and F22. Recrossing events are observed for residues F22 and F33, indicating a possible role of friction effects in the ring-flipping. The results demonstrate the successful application of the metadynamics based approach to estimate ring-flip rates of aromatic residues in BPTI and identify certain limitations of the approach.

Antifreeze Compounds to Allow Survival at Temperatures below 0 C Deg.

2013 ◽  
Vol 711 ◽  
pp. 32-38
Author(s):  
Zdzisław Wiśniowski ◽  
Mateusz Banach ◽  
Irena Roterman
Keyword(s):  
Specific Interaction ◽  
Soluble Proteins ◽  
Hydrophobic Core

The possible mechanism protecting the organisms against the freezing is shown. The presence of highly soluble proteins with no specific interaction allows the organism surviving the temperature below zero Celsius degree. The role of hydrophobic core and its structure (recognized as accordant with the idealized one) appears to be critical for antifreeze function of protein. The possible application of the model for biotechnological preparation of compounds protecting the solutions against freezing is discussed.

scholarly journals Insight into the Interactions of Amyloid β-Sheets with Graphene Flakes: Scrutinizing the Role of Aromatic Residues in Amyloids that Interact with Graphene

ChemPhysChem ◽  
2017 ◽  
Vol 19 (10) ◽  
pp. 1226-1233 ◽  
Author(s):  
Dragana M. Božinovski ◽  
Predrag V. Petrović ◽  
Milivoj R. Belić ◽  
Snežana D. Zarić
Keyword(s):  
Amyloid Β ◽  
Aromatic Residues ◽  
Graphene Flakes ◽  
Β Sheets ◽  
Insight Into

Structural Requirements of Human Ether-a-go-go–  related Gene Channels for Block by Bupivacaine

2007 ◽  
Vol 106 (3) ◽  
pp. 523-531 ◽  
Author(s):  
Cornelia C. Siebrands ◽  
Patrick Friederich
Keyword(s):  
Aromatic Amino Acids ◽  
Selectivity Filter ◽  
Site Directed Mutagenesis ◽  
Xenopus Laevis Oocytes ◽  
Related Gene ◽  
Wild Type ◽  
Aromatic Residues ◽  
Ic50 Value ◽  
Herg Channels

Background Local anesthetics interact with human ether-a-go-go-related gene (HERG) channels via the aromatic amino acids Y652 and F656 in the S6 region. This study aimed to establish whether the residues T623, S624, and V625 residing deeper within the pore are also involved in HERG channel block by bupivacaine. In addition, the study aimed to further define the role of the aromatic residues Y652 and F656 in bupivacaine inhibition by mutating these residues to threonine. Methods Alanine and threonine mutants were generated by site-directed mutagenesis. Electrophysiologic and pharmacologic properties of wild-type and mutant HERG channels were established using two-electrode voltage-clamp recordings of Xenopus laevis oocytes expressing HERG channels. Results Tail currents at -120 mV through HERG wild-type channels were inhibited with an IC50 value of 132 +/- 22 microm (n = 33). Bupivacaine (300 microm) inhibited wild-type tail currents by 62 +/- 12% (n = 7). Inhibition of HERG tail currents by bupivacaine (300 microm) was reduced by all mutations (P < 0.001). The effect was largest for F656A (inhibition 5 +/- 2%, n = 6) in the lower S6 region and for T623A (inhibition 13 +/- 4%, n = 9) near the selectivity filter. Introducing threonine at positions 656 and 652 significantly reduced inhibition by bupivacaine compared with HERG wild type (P < 0.001). Conclusions The authors' results indicate that not only the aromatic residues Y652 and F656 but also residues residing deeper within the pore and close to the selectivity filter of HERG channels are involved in inhibition of HERG channels by the low-affinity blocker bupivacaine.

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