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The structure-activity relationship of marine peptides: a review

INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY 2024年第7期59卷 4437-4445页

作者： Ashaolu, Tolulope Joshua Pham, Bang Phuong Molnar, Zoltan Varga, Laszlo Greff, Babett Duy Tan Univ Inst Global Hlth Innovat Da Nang 550000 Vietnam Duy Tan Univ Fac Med Da Nang 550000 Vietnam Thai Nguyen Univ Agr & Forestry Thai Nguyen 250000 Vietnam Szecheny Istvan Univ Dept Food Sci H-9200 Mosonmagyarovar Hungary

Oceans cover over 70% of the Earth's surface and provide home to structurally diverse marine organisms. These creatures contribute to more than half of the biodiversity of the world and produce several bioactive molecules, including peptides. In the past years, scientific research has been focused on the compositions, sequences and structural features of marine-derived peptides. Based on their amino acid sequences, they have demonstrated a wide range of biological functions, including antithrombotic, antihypertensive, anticancer, antioxidant, antimicrobial, antiageing, anti-inflammatory, immunomodulatory and other multifunctional activities that are based on their structure, hydrophobicity, binding affinity, charge and other factors. This review focuses on novel techniques used to produce marine peptides and explores the structure-function relationships of these peptides derived from representative phyla, namely Cnidaria, Annelida, Mollusca, Arthropoda, Chordata, Echinodermata and Porifera. Furthermore, notable considerations regarding the structure-function basis of marine peptide applications are discussed. Proteins from different marine organisms can be extracted and digested using various methods. The right novel pre-treatments and hydrolytic means coupled with separation and purification techniques can enhance the biofunctional attributes of the derived peptides. These are linked to the relationships between the structure and activity of peptides, dovetailing with their application in the food and healthcare industries. image

关键词： Biological activities marine kingdoms marine organisms peptides structure-function

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Polysaccharide biocomposites with tunable adsorption and antipathogen activity via surface immobilization of chitosan onto modified flax fibers

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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES 2025年 286卷 137929页

作者： Mir, Mariam Wilson, Lee D. Univ Saskatchewan Dept Chem 110 Sci PlThorvaldson Bldg Saskatoon SK S7N 5C9 Canada

Flax fiber modified composite (FFMC) duplex systems with unique sorbent and antipathogen properties were developed by physisorption of chitosan onto modified flax fibers by a facile method. Complementary characterization of the FFMCs (Raman, NMR, and IR, SEM, XRD, TGA and BET analysis) revealed variable composite morphology with incremental chitosan doping and supramolecular interactions between the fiber substrate and immobilized chitosan. Dye adsorption profiles of FFMCs with Rose Bengal corroborated the role of physisorption with an adsorption capacity that rises to 17.9 mg/g, whereas the water sorption capacity reaches an impressive value ca. 11 g/g, which indicated the role of synergism upon chitosan immobilization. Anti-microbial/-fungal properties were supported by antipathogen tests. The FFMCs have high antimicrobial potency toward gram negative (E. coli), gram positive (S. aureus) and a fungal strain (C. albicans) based on the low FFMC dosages required to achieve 100 % microbial elimination. This versatile class of unique biocomposites displayed unique structure-function relationships related to synergistic water sorption and antipathogenic effects, as compared to available literature reports. FFMCs are a diversiform class of biocomposites with unique physicochemical and biological properties that are shown to extend the field of adsorption science and technology from environmental remediation to biomedical devices.

关键词： Flax fiber Chitosan biocomposite Sorbent structure-function Antimicrobial

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The molecular principles underlying diverse functions of the SLC26 family of proteins

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JOURNAL OF BIOLOGICAL CHEMISTRY 2024年第5期300卷 107261-107261页

作者： Takahashi, Satoe Homma, Kazuaki Northwestern Univ Feinberg Sch Med Dept Otolaryngol Head & Neck Surg Chicago IL 60611 USA Univ Chicago Ctr Mech Excitabil Chicago IL 60637 USA Northwestern Univ Hugh Knowles Ctr Clin & Basic Sci Hearing & Its Di Evanston IL 60208 USA

Mammalian SLC26 proteins are membrane-based anion transporters that belong to the large SLC26/SulP family, and many of their variants are associated with hereditary diseases. Recent structural studies revealed a strikingly similar homodimeric molecular architecture for several SLC26 members, implying a shared molecular principle. Now a new question emerges as to how these structurally similar proteins execute diverse physiological functions. In this study, we sought to identify the common versus distinct molecular mechanism among the SLC26 proteins using both naturally occurring and artificial missense changes introduced to SLC26A4, SLC26A5, and SLC26A9. We found: (i) the basic residue at the anion binding site is essential for both anion antiport of SLC26A4 and motor functions of SLC26A5, and its conversion to a nonpolar residue is crucial but not sufficient for the fast uncoupled anion transport in SLC26A9;(ii) the conserved polar residues in the N- and C-terminal cytosolic domains are likely involved in dynamic hydrogen-bonding networks and are essential for anion antiport of SLC26A4 but not for motor (SLC26A5) and uncoupled anion transport (SLC26A9) functions;(iii) the hydrophobic interaction between each protomer's last transmembrane helices, TM14, is not of functional significance in SLC26A9 but crucial for the functions of SLC26A4 and SLC26A5, likely contributing to optimally orient the axis of the relative movements of the core domain with respect to the gate domains within the cell membrane. These findings advance our understanding of the molecular mechanisms underlying the diverse physiological roles of the SLC26 family of proteins.

关键词： structure-function exchanger molecular motor chloride transport patch clamp SLC26A4 pendrin SLC26A5 prestin SLC26A9

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Cryo-EM structures of mouse bestrophin 1 channel in closed and partially open conformations

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MOLECULES AND CELLS 2025年第5期48卷 100208页

作者： Kim, Kwon-Woo Lee, Euna Ko, Ara Hwang, Junmo Park, Kunwoong Lee, Byoung-Cheol Kim, Ki Woo Oh, Won-Jong Kim, Kyuhyung Lim, Hyun-Ho Korea Brain Res Inst KBRI Neurovasc Unit Res Grp Daegu 41062 South Korea DGIST Dept Brain Sci Daegu 42988 South Korea Yonsei Univ Dept Oral Biol Div Physiol Coll Dent Seoul 03722 South Korea

Bestrophin 1 (BEST1) channels are calcium-activated Cl- channels involved in diverse physiological processes, including gliotransmitter release in astrocytes. Although human and chicken BEST1 orthologs have been extensively studied, the structural and functional properties of mouse BEST1 (mBEST1) remain poorly understood. In this study, we characterized the structure-function of mBEST1-BF, a C-terminally tagged variant, using whole-cell patch-clamp recordings, surface biotinylation assays, and single-particle cryo-electron microscopy. Cryo-electron microscopy structural analysis of mBEST1-BF revealed closed and partially open conformations. Comparative analysis with human and chicken BEST1 orthologs highlighted conserved calcium-binding and gating mechanisms, with distinct features in mBEST1, including a wider aperture sufficient to accommodate dehydrated Cl- ions and potential anion-binding sites near Val205 and Gln208 residues. The disordered C-terminal region of mBEST1 remains unresolved, suggesting it may require stabilizing factors for structural determination. Additionally, the autoinhibitory domain, which includes Ser354, likely plays a key role in regulating gating, with Ser354 potentially serving as a phosphorylation site that modulates channel activity. Our findings provide structural and functional insights into mBEST1 and suggest mechanisms underlying its unique gating and ion (c) 2025 The Author(s). Published by Elsevier Inc. on behalf of Korean Society for Molecular and Cellular Biology. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/).

关键词： Bestrophin 1 Calcium-activated chloride channel Gating Ion permeation structure-function

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High temperature induces investment in phloem and increases sucrose accumulation in grapevine

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TREES-structure AND function 2024年第5期38卷 1151-1159页

作者： Wolberg, Shunamit Dumbur, Rita Netzer, Yishai Gruenzweig, Jose M. Shtein, Ilana Eastern Reg Res & Dev Ctr Ariel Israel Hebrew Univ Jerusalem Robert H Smith Inst Plant Sci & Genet Agr Robert H Smith Fac Agr Food & Environm Rehovot Israel Ariel Univ Dept Chem & Biotech Engn IL-40700 Ariel Israel Ariel Univ Dept Mol Biol IL-40700 Ariel Israel

There's a lack of studies on the structure-function aspect of linking non-structural carbohydrates to temperature, in particular phloem structure is yet a largely neglected subject. We studied gas exchange parameters and in parallel examined functional anatomy and non-structural carbohydrates status in leaf blades, petioles and branches in 'Cabernet Sauvignon' grapevines grown under three temperature regimes (22/16 degrees C, 28/22 degrees C, 34/28 degrees C day/night). After two months of growth, water use efficiency was the highest at 34 degrees C. The individual organs size became progressively smaller as the temperatures increased, and was the smallest at 34 degrees C for branch and petiole diameter, and for leaf thickness. The relative xylem cross-sectional area was largely not influenced by the temperature regime. In contrast, phloem cross-sectional area was significantly increased at high temperature in branches and petioles, and became 30% higher at 34 degrees C in branches compared to 22 degrees C. The leaves had the highest non-structural carbohydrates concentration compared to petioles and branches. Sucrose content exhibited a temperature-dependent increase both in branches and petioles, and to some extent also in leaves, while starch, fructose and glucose content did not exhibit any statistically significant temperature trends. In grapevine, sucrose is the main non-structural carbohydrate used for long-distance transport. Our results indicate temperature dependent increased investment in phloem development in parallel with increased main long-distance transported sugar (sucrose) accumulation. Phloem and xylem development were apparently uncoupled, implying a differential cambium activity for each tissue. Our study could have wide structural-functional implications in the ongoing climate change scenario.

关键词： Vitis vinifera Grapevine Xylem Phloem structure-function Sucrose Anatomy Temperature Carbohydrates

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Sugar binding of sodium-glucose cotransporters analyzed by voltage-clamp fluorometry

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JOURNAL OF BIOLOGICAL CHEMISTRY 2024年第5期300卷 107215-107215页

作者： Watabe, Erika Kawanabe, Akira Kamitori, Kazuyo Ichihara, Satoko Fujiwara, Yuichiro Kagawa Univ Fac Med Lab Mol Physiol & Biophys Miki Cho Takamatsu Kagawa Japan Kagawa Univ Int Inst Rare Sugar Res & Educ Miki Cho Takamatsu Kagawa Japan Hiroshima Univ Grad Sch Biomed & Hlth Sci Lab Physiol & Biophys Hiroshima Hiroshima Japan

Sugar absorption is crucial for life and relies on glucose transporters, including sodium-glucose cotransporters (SGLTs). Although the structure of SGLTs has been resolved, the substrate selectivity of SGLTs across diverse isoforms has not been determined owing to the complex substrate- recognition processes and limited analysis methods. Therefore, this study used voltage-clamp fl uorometry (VCF) to explore the substrate-binding affinities of human SGLT1 in Xenopus oocytes. VCF analysis revealed high-affinity binding of D-glucose and D-galactose, which are known transported substrates. D-fructose, which is not a transported substrate, also bound to SGLT1, suggesting potential recognition despite the lack of transport activity. VCF analysis using the T287N mutant of the substrate-binding pocket, which has reduced Dglucose transport capacity, showed that its D-galactose-binding affinity exceeded its D-glucose-binding affinity. This suggests that the change in the VCF signal was due to substrate binding to the binding pocket. Both D-fructose and L-sorbose showed similar binding affinities, indicating that SGLT1 preferentially binds to pyranose-form sugars, including D-fructopyranose. Electrophysiological analysis confirmed that D-fructose binding did not affect the SGLT1 transport function. The signifi- cance of the VCF assay lies in its ability to measure sugar- protein interactions in living cells, thereby bridging the gap between structural analyses and functional characterizations of sugar transporters. Our fi ndings also provide insights into SGLT substrate selectivity and the potential for developing medicines with reduced side effects by targeting non-glucose sugars with low bioreactivity.

关键词： membrane transport sugar transport structure-function substrate specificity voltage-clamp fluorometry SGLT substrate recognition

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Standard automated perimetry for glaucoma and diseases of the retina and visual pathways: Current and future perspectives

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PROGRESS IN RETINAL AND EYE RESEARCH 2025年 104卷 101307页

作者： Phu, Jack Khuu, Sieu K. Nivison-Smith, Lisa Kalloniatis, Michael Univ New South Wales Sydney Sch Optometry & Vis Sci Gate 14 Barker St Rupert Myers Bldg South Wing Kensington NSW 2052 Australia Univ New South Wales Ctr Eye Hlth Kensington NSW Australia Univ Sydney Fac Med & Hlth Sydney NSW Australia Concord Repatriat Gen Hosp Concord Clin Sch Concord NSW Australia Deakin Univ Sch Med Optometry Waurn Ponds Vic Australia Univ Houston Coll Optometry Houston TX USA

Static automated perimetry (SAP) remains a mainstay of functional assessment of the visual field in diseases of the visual pathway, such as glaucoma and age-related macular degeneration. The fundamental psychophysical task of responding to stimuli of different levels of contrast has remained minimally changed since its inception in the 1980s, and this is potentially the root of several unresolved issues involving the technique. Enduring issues include the optimisation of SAP parameters for maximising defect detection, the influence of subjective behaviour on the response, structure-function discordance, and ageing- and disease-related changes of the visual pathway. Addressing these issues has been a focus of our research program and is the subject of this manuscript. We will review some of the basic psychophysical principles and methods that have contributed to the development of SAP and their contributions to its output measurements. Parameters that are interrogated include stimulus size and background luminance and their modification to improve defect defection in glaucoma and age-related macular degeneration. We propose frameworks for optimising testing parameters and leveraging the results for changing clinical care. In our pursuit of optimising the structure-function relationship in the eye, several areas of research have been developed and explored, including: the reconciliation of subjective responses in perimetry;by minimising sources of biases, such as Method of Limits we have been able to equate static and kinetic perimetry outputs in relation to underlying structural loci. This also formed the basis for our clustering framework, which groups together statistically similar structural and functional test locations to maximise structure-function concordance. Throughout the manuscript, we review the scientific underpinnings of clinical measurements, framing application into real-world patients to improve clinical practice.

关键词： SITA Psychophysics Thresholding Visual fields Static automated perimetry Kinetic perimetry structure-function Macula Dark adaptation 24-2 Glaucoma

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The carboxy terminus causes interfacial assembly of oleate hydratase on a membrane bilayer

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JOURNAL OF BIOLOGICAL CHEMISTRY 2024年第2期300卷 105627-105627页

作者： Radka, Christopher D. Grace, Christy R. Hasdemir, Hale S. Li, Yupeng Rodriguez, Carlos C. Rodrigues, Patrick Oldham, Michael L. Qayyum, M. Zuhaib Pitre, Aaron MacCain, William J. Kalathur, Ravi C. Tajkhorshid, Emad Rock, Charles O. Univ Kentucky Dept Microbiol Immunol & Mol Genet Lexington KY 40506 USA St Jude Childrens Res Hosp Dept Host Microbe Interact Memphis TN 38105 USA St Jude Childrens Res Hosp Dept Struct Biol Memphis TN USA Univ Illinois Beckman Inst Adv Sci & Technol Dept Biochem Theoret & Computat Biophys GrpNIH Resource Macrom Urbana IL USA Univ Illinois Beckman Inst Adv Sci & Technol Ctr Biophys & Quantitat Biol NIH Resource Macromol Modeling & Visualizat Urbana IL USA St Jude Childrens Res Hosp Hartwell Ctr Biotechnol Memphis TN USA St Jude Childrens Res Hosp Cell & Tissue Imaging Ctr Memphis TN USA

The soluble flavoprotein oleate hydratase (OhyA) hydrates the 9-cis double bond of unsaturated fatty acids. OhyA substrates are embedded in membrane bilayers;OhyA must remove the fatty acid from the bilayer and enclose it in the active site. Here, we show that the positively charged helixturn-helix motif in the carboxy terminus (CTD) is responsible for interacting with the negatively charged phosphatidylglycerol (PG) bilayer. Super-resolution microscopy of Staphylococcus aureus cells expressing green fluorescent protein fused to OhyA or the CTD sequence shows subcellular localization along the cellular boundary, indicating OhyA is membraneassociated and the CTD sequence is sufficient for membrane recruitment. Using cryo-electron microscopy, we solved the OhyA dimer structure and conducted 3D variability analysis of the reconstructions to assess CTD flexibility. Our surface plasmon resonance experiments corroborated that OhyA binds the PG bilayer with nanomolar affinity and we found the CTD sequence has intrinsic PG binding properties. We determined that the nuclear magnetic resonance structure of a peptide containing the CTD sequence resembles the OhyA crystal structure. We observed intermolecular NOE from PG liposome protons next to the phosphate group to the CTD peptide. The addition of paramagnetic MnCl2 indicated the CTD peptide binds the PG surface but does not insert into the bilayer. Molecular dynamics simulations, supported by site-directed mutagenesis experiments, identify key residues in the helixturn-helix that drive membrane association. The data show that the OhyA CTD binds the phosphate layer of the PG surface to obtain bilayer-embedded unsaturated fatty acids.

关键词： oleate hydratase (OhyA) phospholipid membrane lipid binding protein lipid-protein interaction protein structure structure-function amphipathic helices interfacial enzyme peripheral membrane protein

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A plant mutant screen CURE integrated with core biology concepts showed effectiveness in course design and students' perceived learning gains

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BIOCHEMISTRY AND MOLECULAR BIOLOGY EDUCATION 2025年第1期53卷 57-69页

作者： Liu, Jinjie Benning, Christoph Michigan State Univ Biol Sci Program E Lansing MI 48824 USA Michigan State Univ MSU DOE Plant Res Lab E Lansing MI USA Michigan State Univ Dept Biochem & Mol Biol E Lansing MI USA Michigan State Univ Dept Plant Biol E Lansing MI USA

Course-based undergraduate research experiences (CUREs) provide students with valuable opportunities to engage in research in a classroom setting, expanding access to research opportunities for undergraduates, fostering inclusive research and learning environments, and bridging the gap between the research and education communities. While scientific practices, integral to the scientific discovery process, have been widely implemented in CUREs, there have been relatively few reports emphasizing the incorporation of core biology concepts into CURE curricula. In this study, we present a CURE that integrates core biology concepts, including genetic information flow, phenotype-genotype relationships, mutations and mutants, and structure-function relationships, within the context of mutant screening and gene loci identification. The design of this laboratory course aligns with key CURE criteria, as demonstrated by data collected through the laboratory course assessment survey (LCAS). The survey of undergraduate research experiences (SURE) demonstrates students' learning gains in both course-directed skills and transferrable skills following their participation in the CURE. Additionally, concept survey data reflect students' self-perceived understanding of the aforementioned core biological concepts. Given that genetic mutant screens are central to the study of gene function in biology, we anticipate that this CURE holds potential value for educators and researchers who are interested in designing and implementing a mutant screen CURE in their classrooms. This can be accomplished through independent research or by establishing partnerships between different units or institutions.

关键词： core biology concepts course-based undergraduate research experiences (CUREs) genetic information flow LCAS mutation and mutants phenotype-genotype structure-function SURE

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Structural engineering of antimicrobials for optimal broad-spectrum activity

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Green Chemical Engineering 2024年第4期5卷 473-482页

作者： Arunmozhiarasi Armugam Diane S.W.Lim Siti Nurhanna Riduan Shook Pui Chan Jerome Asugan Yugen Zhang Institute of Bioengineering and Bioimaging 31 Biopolis WayThe Nanos#07-01138669Singapore Institute of Sustainability for Chemicals Energy and Environment(ISCE2)Agency for ScienceTechnology and Research(A^(*)STAR)1 Pesek Road Jurong Island627833Singapore Diploma in Biomedical Science School of Chemical and Life SciencesSingapore Polytechnic500 Dover Road139651Singapore

Antimicrobial materials are a crucial component in eradicating and managing the spread of infectious *** are expected to act on a broad-spectrum of microbes,including emerging pathogens which could cause the next Disease ***,we reassessed a series of antimicrobial imidazolium polymers on our shelves and uncovered extended functionality through dual modes of *** redesigning their structures,a truly broadspectrum antimicrobial material with optimized activity against bacteria(G+ve,G-ve)and fungi,as well as enveloped and non-enveloped viruses was *** demonstrated that the imidazolium polymer exhibits dual modes of function against microbes:targeting the microbial membrane and binding *** latter DNA binding affinity was found to be key against non-enveloped *** this insight,we designed small molecule compounds that exhibited optimum broad-spectrum antimicrobial activity and excellent efficacy against ESKAPE group of pathogens that are responsible for some of the deadliest nosocomial infections *** results could also shed light on the design of broad-spectrum antimicrobial compounds against Disease X.

关键词： Broad-spectrum Antimicrobial Polyimidazolium structure-function Membrane active

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