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Ефремов Роман Гербертович

Московский институт электроники и математики им. А.Н. Тихонова

Профиль на hse.ru ↗ тел.: +7 (495) 916-88-76 | 15129 | +7 (903) 743-16-56
Публикаций
127
Языков
2
Наград
5
Конференций
3
Профиль Публикации (127) Курсы (4)

Профессиональные интересы

Вычислительная биологиякомпьютерная биологиямолекулярное моделированиеструктура и динамика биомолекулбиофизика

Должности

  • Профессор — Московский институт электроники и математики им. А.Н. Тихонова, Департамент прикладной математики

Био

  • · Начал работать в НИУ ВШЭ в 2013 году.
  • · Научно-педагогический стаж: 42 года.

Образование

  • 2007 · Ученое звание: Профессор
  • 2000 · Доктор физико-математических наук
  • 1986 · Кандидат физико-математических наук
  • 1983 · Специалитет: Московский инженерно-физический институт, специальность «Дозиметрия и защита», квалификация «Инженер-физик»

Награды и поощрения

  • · Участие в научных советах и обществах: член Ученого Совета ИБХ РАН; член трех специализированных диссертационных советов (ИБХ РАН, МГУ, ГУ НИИ БМХ РАМН); член Американского химического общества; член Биофизического общества (США).
  • · Надбавка за публикацию в журнале из Списка А (и приравненном к нему научном издании) (2025–2026, 2024–2025, 2023–2024)
  • · Надбавка за публикацию в международном рецензируемом научном издании (2022–2023, 2021–2022, 2019–2021)
  • · Надбавка за статью в зарубежном рецензируемом журнале (2014–2016)
  • · Надбавка за статью в зарубежном рецензируемом научном издании (2016–2018)

Гранты и проекты

  • 2016 · Грант Российского научного фонда «Компьютерный анализ структурно-функциональных аспектов олигомеризации трансмембранных доменов рецепторов сигнальных систем клетки», 2014-2016 гг., руководитель.
  • 2016 · Грант Российского научного фонда «Молекулярные технологии управления нейросигнализацией», 2014-2016 гг., отв. соисполнитель.
  • 2017 · Грант Программы Президиума РАН «Молекулярная и клеточная биология», тема: «Молекулярное моделирование пептидов и белков в мембранах как фундаментальная основа для рационального конструирования новых биологически активных соединений», 2013-2017 гг., руководитель.
  • 2014 · Грант Программы Президиума РАН № 27 «Основы фундаментальных исследований нанотехнологий и наноматериалов», тема: «Новые вычислительные технологии мультимасштабного моделирования мезоскопических биомембранных систем: от понимания фундаментальных принципов структурно-динамического поведения – к созданию наноструктур для биомедицинских приложений», 2012-2014 гг., руководитель.
  • 2015 · Грант РФФИ «Коллективные молекулярные движения, кластеры и флуктуации в гидратированных липидных бислоях и их роль в структурно-динамическом поведении клеточных мембран», 2013-2015 гг., руководитель.
  • 2018 · Грант РФФИ «Клеточные мембраны как стохастические динамические системы: от атомистического моделирования – к рациональному конструированию новых мембранных материалов», 2016-2018 гг., руководитель.

Конференции (3)

Показать все
  • · 2016: Актуальные вопросы биологической физики и химии БФФХ-2016 (Севастополь). Доклад: Оценка влияния среды на димеризацию трансмембранных доменов гликофорина А в компьютерном эксперименте
  • · 2016: Khujand Symposium on Computational Materials and Biological Sciences 2016 (Худжанд). Доклад: Helix-helix interactions in membranes: focus on lipids
  • · 2014: Dushanbe Symposium on Computational Materials and Biological Sciences DSCMBS-2014 (Душанбе). Доклад: The adaptable lipid matrix promotes transmembrane helices association in membranes

Идентификаторы исследователя

Публикации (127)

Structure-Based Rational Design of Small α-Helical Peptides with Broad-Spectrum Activity Against Multidrug-Resistant Pathogens

2023 · ARTICLE · en

A series of small (7- to 12-mer) amphipathic cationic peptides were designed and synthesized with the ultimate goal of creating a set of short helical peptides with broad-range bactericidal activity and good selectivity toward the bacterial cells. Activity analysis identified a lead 12-mer peptide 8b with broad spectrum activity against Gram-positive (MIC=3.1-6.2 µg/mL) and Gram-negative (MIC=6.2-12.5 µg/mL) bacteria, including multidrug-resistant strains, and good selectivity towards prokaryotic cells versus eukaryotic cells (HC50=280 µg/mL and >75% cell viability at 150 µg/mL). The fast membranolytic action of 8b was demonstrated by a calcein dye leakage assay and confirmed using scanning electron microscopy. Analysis of 8b and its closest analogs by CD and NMR spectroscopy indicated their irregular spatial structure in water. A lipid bilayer induced the formation of an amphipathic helix in 8b and other 12-mer peptides, but not in the shorter peptides. Molecular dynamics simulations provided detailed information about the interaction of 8b and its closest analogs with bacterial and mammalian membranes and revealed the roles of particular amino acids in the peptides’ activity and selectivity.

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Structural mechanism of ionic conductivity of the TRPV1 channel

2023 · ARTICLE · en

In many types of ion channels, certain internal surface areas of their transmembrane pores are lined with non-polar residues forming a kind of "belts" of hydrophobicity. When a channel resides in a closed/inactivated state, this prevents spontaneous diffusion of water and ions through the membrane. At the same time, when a channel is activated and, consequently, the pore radius increases, especially in the narrowest places (the so-called " activation gates"), effective transport of water molecules and ions across the membrane is observed. Such effect is known as “hydrophobic gating”, and it can block water and ion transport without full occlusion of the pore (typically with a radius of Cα atoms ≤ 4 Å) [1]. Apparently, the transport through the hydrophobic gates may by facilitated by some polar "helper groups" of amino acid residues that assist polar/charged substances (like water and ions) to overcome the energy barrier created by non-polar environment.

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Specific binding of the α-component of the lantibiotic lichenicidin to the peptidoglycan precursor lipid II predetermines its antimicrobial activity

2023 · ARTICLE · en

To date, a number of lantibiotics have been shown to use lipid II — a highly conserved peptidoglycan precursor in the cytoplasmic membrane of bacteria — as their molecular target. The α-component (Lchα) of the two-component lantibiotic lichenicidin (Lchα), previously isolated from the Bacillus licheniformis VK21 strain, seems to contain two putative lipid II binding sites in its N-terminal and C-terminal domains. Using NMR spectroscopy in DPC micelles, we obtained convincing evidence that the C-terminal mersacidin-like site is involved in the interaction with lipid II. These data were confirmed by the MD simulations. The contact area of lipid II includes pyrophosphate and disaccharide residues along with the first isoprene units of bactoprenol. MD also showed the potential for the formation of a stable N-terminal nisin-like complex, however, the conditions necessary for its implementation in vitro remain unknown. Overall, our results clarify the picture of two component lantibiotics mechanism of antimicrobial action.

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Diversity of Structural, Dynamic, and Environmental Effects Explain a Distinctive Functional Role of Transmembrane Domains in the Insulin Receptor Subfamily

2023 · ARTICLE · en

Human InsR, IGF1R, and IRR receptor tyrosine kinases (RTK) of the insulin receptor subfamily play an important role in signaling pathways for a wide range of physiological processes and are directly associated with many pathologies, including neurodegenerative diseases. The disulfide-linked dimeric structure of these receptors is unique among RTKs. Sharing high sequence and structure homology, the receptors differ dramatically in their localization, expression, and functions. In this work, using high-resolution NMR spectroscopy supported by atomistic computer modeling, conformational variability of the transmembrane domains and their interactions with surrounding lipids were found to differ significantly between representatives of the subfamily. Therefore, we suggest that the heterogeneous and highly dynamic membrane environment should be taken into account in the observed diversity of the structural/dynamic organization and mechanisms of activation of InsR, IGF1R, and IRR receptors. This membrane-mediated control of receptor signaling offers an attractive prospect for the development of new targeted therapies for diseases associated with dysfunction of insulin subfamily receptors.

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Crystal Structure of Bright Fluorescent Protein BrUSLEE with Subnanosecond Fluorescence Lifetime; Electric and Dynamic Properties

2023 · ARTICLE · en

The rapid development of new microscopy techniques for cell biology has exposed the need for genetically encoded fluorescent tags with special properties. Fluorescent biomarkers of the same color and spectral range and different fluorescent lifetimes (FLs) became useful for fluorescent lifetime image microscopy (FLIM). One such tag, the green fluorescent protein BrUSLEE (Bright Ultimately Short Lifetime Enhanced Emitter), having an extremely short subnanosecond component of fluorescence lifetime (FL~0.66 ns) and exceptional fluorescence brightness, was designed for FLIM experiments. Here, we present the X-ray structure and discuss the structure-functional relations of BrUSLEE. Its development from the EGFP (enhanced green fluorescent proteins) precursor (FL~2.83 ns) resulted in a change of the chromophore microenvironment due to a significant alteration in the side chain conformations. To get further insight into molecular details explaining the observed differences in the photophysical properties of these proteins, we studied their structural, dynamic, and electric properties by all-atom molecular-dynamics simulations in an aqueous solution. It has been shown that compared to BrUSLEE, the mobility of the chromophore in the EGFP is noticeably limited by nonbonded interactions (mainly H-bonds) with the neighboring residues.

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On a mechanistic impact of transmembrane tetramerization in the pathological activation of RTKs

2023 · ARTICLE · en

Constitutive activation of receptor tyrosine kinases (RTKs) via different mutations has a strong impact on the development of severe human disorders, including cancer. Here we propose a putative activation scenario of RTKs, whereby transmembrane (TM) mutations can also promote higher-order oligomerization of the receptors that leads to the subsequent ligand-free activation. We illustrate this scenario using a computational modelling framework comprising sequence-based structure prediction and all-atom 1 µs molecular dynamics (MD) simulations in a lipid membrane for a previously characterised oncogenic TM mutation V536E in platelet-derived growth factor receptor alpha (PDGFRA). We show that in the course of MD simulations the mutant TM tetramer retains stable and compact configuration strengthened by tight protein-protein interactions, while the wild type TM tetramer demonstrates looser packing and a tendency to dissociate. Moreover, the mutation affects the characteristic motions of mutated TM helical segments by introducing additional non-covalent crosslinks in the middle of the TM tetramer, which operate as mechanical hinges. This leads to dynamic decoupling of the C-termini from the rigidified N-terminal parts and facilitates more pronounced possible displacement between the C-termini of the mutant TM helical regions that can provide more freedom for mutual rearrangement of the kinase domains located downstream. Our results for the V536E mutation in the context of PDGFRA TM tetramer allow for the possibility that the effect of oncogenic TM mutations can go beyond alternating the structure and dynamics of TM dimeric states and might also promote the formation of higher-order oligomers directly contributing to ligand-independent signalling effectuated by PDGFRA and other RTKs.

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Fighting Celiac Disease: Improvement of pH Stability of Cathepsin L In Vitro by Computational Design

2023 · ARTICLE · en

Roughly 1% of the global population is susceptible to the celiac disease (CD) — inheritable autoimmune inflammation of the small intestine, caused by intolerance to gliadin proteins present in wheat, rye and barley grains, and called gluten in wheat. Classic treatment is a life-long gluten-free diet, which is constraining and costly. Alternative approach is based upon development and oral reception of the effective peptidases that degrade in the stomach immunogenic proline- and glutamine-rich gliadin peptides, which cause the severe reaction in the intestine. In the previous research we have established that the major digestive peptidase of an insect Tribolium castaneum — cathepsin L — hydrolyzes immunogenic prolamins after Gln residues; although, this enzyme is unstable in the extremely acidic environment (pH 2–4) of the human stomach and cannot be used as the digestive aid. In this work, using molecular dynamics simulations, we discover the probable cause of pH-instability of cathepsin L — loss of the catalytically-competent rotameric state of one of the active site residues, His 275. Trying to “fix” the correct orientation of this residue, we suggested a V277A mutant variant, which extended the range of stability to the acidic environment, retaining the most of activity. We suggest this protein as a lead glutenase for the development of oral medical preparation that fights CD and gluten intolerance in the susceptible people.

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Inconspicuous yet indispensable: the coronavirus spike transmembrane domain

2023 · ARTICLE · en

Membrane-spanning portions of proteins’ polypeptide chains are commonly known as their transmembrane domains (TMDs). The structural organisation and dynamic behaviour of TMDs from proteins of various families, be that receptors, ion channels, enzymes etc., have been under scrutiny on the part of the scientific community for the last few decades. The reason for such attention is that, apart from their obvious role as an “anchor” in ensuring the correct orientation of the protein’s extra-membrane domains (in most cases functionally important), TMDs often actively and directly contribute to the operation of “the protein machine”. They are capable of transmitting signals across the membrane, interacting with adjacent TMDs and membrane-proximal domains, as well as with various ligands, etc. Structural data on TMD arrangement are still fragmentary at best due to their complex molecular organisation as, most commonly, dynamic oligomers, as well as due to the challenges related to experimental studies thereof. Inter alia, this is especially true for viral fusion proteins, which have been the focus of numerous studies for quite some time, but have provoked unprecedented interest in view of the SARS-CoV-2 pandemic. However, despite numerous structurecentred studies of the spike (S) protein effectuating target cell entry in coronaviruses, structural data on the TMD as part of the entire spike protein are still incomplete, whereas this segment is known to be crucial to the spike’s fusogenic activity. Therefore, in attempting to bring together currently available data on the structure and dynamics of spike proteins’ TMDs, the present review aims to tackle a highly pertinent task and contribute to a better understanding of the molecular mechanisms underlying virus-mediated fusion, also offering a rationale for the design of novel efficacious methods for the treatment of infectious diseases caused by SARS-CoV-2 and related viruses.

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Structural Analysis and Activity Correlation of Amphiphilic Cyclic Antimicrobial Peptides Derived from the [W4R4] Scaffold

2023 · ARTICLE · en

In our ongoing quest to design effective antimicrobial peptides (AMPs), this study aimed to elucidate the mechanisms governing cyclic amphiphilic AMPs and their interactions with membranes. The objective was to discern the nature of these interactions and understand how peptide sequence and structure influence antimicrobial activity. We introduced modifications into the established cyclic AMP peptide, [W4R4], incorporating an extra aromatic hydrophobic residue (W), a positively charged residue (R), or the unique 2,5-diketopiperazine (DKP). This study systematically explored the structure–activity relationships (SARs) of a series of cyclic peptides derived from the [W4R4] scaffold, including the first synthesis and evaluation of [W4R4(DKP)]. Structural, dynamic, hydrophobic, and membrane-binding properties of four cyclic peptides ([W4R4], [W5R4], [W4R5], [W4R4(DKP)]) were explored using molecular dynamics simulations within a DOPC/DOPG lipid bilayer that mimics the bacterial membrane. The results revealed distinct SARs linking antimicrobial activity to parameters such as conformational plasticity, immersion depth in the bilayer, and population of the membrane binding mode. Notably, [W4R5] exhibited an optimal “activity/binding to the bacterial membrane” pattern. This multidisciplinary approach efficiently decoded finely regulated SAR profiles, laying a foundation for the rational design of novel antimicrobial peptides.

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Small Amphiphilic Peptides: Activity Against Broad Range of Drug-Resistant Bacteria and Structural Insight into Membranolytic Properties

2022 · ARTICLE · en

We report the synthesis and antibacterial activities of a series of amphiphilic membrane-active peptides composed, in part, of various non-genetically coded hydrophobic amino acids. Lead cyclic peptides, 8C and 9C, showed broad-spectrum activity against drug-resistant Gram-positive (MIC=1.5-6.2 µg/mL) and Gram-negative (MIC=12.5-25 µg/mL) bacteria. Cytotoxicity study showed the predominant lethal action of the peptides against bacteria as compared with mammalian cells. A plasma stability study revealed approximately 2-fold higher stability of lead cyclic peptides as compared to their linear counterparts after 24 h incubation. A calcein dye leakage experiment revealed the membranolytic effect of the cyclic peptides. Nuclear magnetic resonance spectroscopy and molecular dynamics simulations studies of the interaction of the peptides with phospholipid bilayer provided a solid structural basis explaining the membranolytic action of the peptides with atomistic details. These results highlight the potential of newly designed amphiphilic peptides as the next generation of peptide-based antibiotics.

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Курсы (4)