Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 1.296
Filtrar
1.
Phys Chem Chem Phys ; 22(3): 1107-1114, 2020 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-31895350

RESUMO

Super-resolution imaging techniques have largely improved our capabilities to visualize nanometric structures in biological systems. Their application further permits the quantitation relevant parameters to determine the molecular organization and stoichiometry in cells. However, the inherently stochastic nature of fluorescence emission and labeling strategies imposes the use of dedicated methods to accurately estimate these parameters. Here, we describe a Bayesian approach to precisely quantitate the relative abundance of molecular aggregates of different stoichiometry from segmented images. The distribution of proxies for the number of molecules in a cluster, such as the number of localizations or the fluorescence intensity, is fitted via a nested sampling algorithm to compare mixture models of increasing complexity and thus determine the optimum number of mixture components and their weights. We test the performance of the algorithm on in silico data as a function of the number of data points, threshold, and distribution shape. We compare these results to those obtained with other statistical methods, showing the improved performance of our approach. Our method provides a robust tool for model selection in fitting data extracted from fluorescence imaging, thus improving the precision of parameter determination. Importantly, the largest benefit of this method occurs for small-statistics or incomplete datasets, enabling an accurate analysis at the single image level. We further present the results of its application to experimental data obtained from the super-resolution imaging of dynein in HeLa cells, confirming the presence of a mixed population of cytoplasmic single motors and higher-order structures.


Assuntos
Imagem Molecular , Proteínas/química , Teorema de Bayes , Modelos Químicos , Proteínas/ultraestrutura
2.
Molecules ; 24(18)2019 Sep 10.
Artigo em Inglês | MEDLINE | ID: mdl-31510014

RESUMO

Normal mode analysis (NMA) is a technique that can be used to describe the flexible states accessible to a protein about an equilibrium position. These states have been shown repeatedly to have functional significance. NMA is probably the least computationally expensive method for studying the dynamics of macromolecules, and advances in computer technology and algorithms for calculating normal modes over the last 20 years have made it nearly trivial for all but the largest systems. Despite this, it is still uncommon for NMA to be used as a component of the analysis of a structural study. In this review, we will describe NMA, outline its advantages and limitations, explain what can and cannot be learned from it, and address some criticisms and concerns that have been voiced about it. We will then review the most commonly used techniques for reducing the computational cost of this method and identify the web services making use of these methods. We will illustrate several of their possible uses with recent examples from the literature. We conclude by recommending that NMA become one of the standard tools employed in any structural study.


Assuntos
Modelos Teóricos , Conformação Proteica , Proteínas/química , Algoritmos , Cristalografia por Raios X , Proteínas/ultraestrutura
3.
ALTEX ; 36(3): 518-520, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31329264

RESUMO

Quantification of fluorescence colocalization and intensity of strongly overlapping cells, e.g., neuronal cultures, is challenging for programs that use image segmentation to identify cells as individual objects. Moreover, learning to use and apply one of the large imaging packages can be very time- and/or resource-demanding. Therefore, we developed the free and highly interactive image analysis program SUIKER (program for SUperImposing KEy Regions) that quantifies colocalization of different proteins or other features over an entire image field. The software allows definition of cellular subareas by subtraction ("punching out") of structures identified in one channel from structures in a second channel. This allows, e.g., definition of neurites without cell bodies. Moreover, normalization to live or total cell numbers is possible. Providing a detailed manual that contains image analysis examples, we demonstrate how the program uses a combination of colocalization information and fluorescence intensity to quantify carbohydrate-specific stains on neurites. SUIKER can import any multichannel histology or cell culture image, builds on user-guided threshold setting, batch processes large image stacks, and exports all data (including the settings, results and metadata) in flexible formats to be used in Excel.


Assuntos
Antígenos/ultraestrutura , Processamento de Imagem Assistida por Computador , Neuritos/ultraestrutura , Organelas/ultraestrutura , Software , Algoritmos , Animais , Humanos , Proteínas/ultraestrutura
4.
Nat Commun ; 10(1): 2511, 2019 06 07.
Artigo em Inglês | MEDLINE | ID: mdl-31175284

RESUMO

Chemical shifts (CS) are determined from NMR experiments and represent the resonance frequency of the spin of atoms in a magnetic field. They contain a mixture of information, encompassing the in-solution conformations a protein adopts, as well as the movements it performs. Due to their intrinsically multi-faceted nature, CS are difficult to interpret and visualize. Classical approaches for the analysis of CS aim to extract specific protein-related properties, thus discarding a large amount of information that cannot be directly linked to structural features of the protein. Here we propose an autoencoder-based method, called ShiftCrypt, that provides a way to analyze, compare and interpret CS in their native, multidimensional space. We show that ShiftCrypt conserves information about the most common structural features. In addition, it can be used to identify hidden similarities between diverse proteins and peptides, and differences between the same protein in two different binding states.


Assuntos
Ressonância Magnética Nuclear Biomolecular/métodos , Proteínas/ultraestrutura , Aminoácidos , Fenômenos Biofísicos , Imagem por Ressonância Magnética , Espectroscopia de Ressonância Magnética , Modelos Moleculares , Estrutura Secundária de Proteína
5.
Nature ; 569(7756): 438-442, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31068697

RESUMO

Symmetrical protein cages have evolved to fulfil diverse roles in nature, including compartmentalization and cargo delivery1, and have inspired synthetic biologists to create novel protein assemblies via the precise manipulation of protein-protein interfaces. Despite the impressive array of protein cages produced in the laboratory, the design of inducible assemblies remains challenging2,3. Here we demonstrate an ultra-stable artificial protein cage, the assembly and disassembly of which can be controlled by metal coordination at the protein-protein interfaces. The addition of a gold (I)-triphenylphosphine compound to a cysteine-substituted, 11-mer protein ring triggers supramolecular self-assembly, which generates monodisperse cage structures with masses greater than 2 MDa. The geometry of these structures is based on the Archimedean snub cube and is, to our knowledge, unprecedented. Cryo-electron microscopy confirms that the assemblies are held together by 120 S-Aui-S staples between the protein oligomers, and exist in two chiral forms. The cage shows extreme chemical and thermal stability, yet it readily disassembles upon exposure to reducing agents. As well as gold, mercury(II) is also found to enable formation of the protein cage. This work establishes an approach for linking protein components into robust, higher-order structures, and expands the design space available for supramolecular assemblies to include previously unexplored geometries.


Assuntos
Ouro/química , Proteínas/química , Microscopia Crioeletrônica , Cisteína/química , Mercúrio/química , Modelos Moleculares , Proteínas/ultraestrutura
7.
Nature ; 567(7746): 127-131, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30814734

RESUMO

The GABAB (γ-aminobutyric acid type B) receptor is one of the principal inhibitory neurotransmitter receptors in the brain, and it signals through heterotrimeric G proteins to activate a variety of effectors, including G-protein-coupled inwardly rectifying potassium channels (GIRKs)1,2. GABAB-receptor signalling is tightly regulated by auxiliary subunits called KCTDs, which control the kinetics of GIRK activation and desensitization3-5. However, the mechanistic basis for KCTD modulation of GABAB signalling remains incompletely understood. Here, using a combination of X-ray crystallography, electron microscopy, and functional and biochemical experiments, we reveal the molecular details of KCTD binding to both GABAB receptors and G-protein ßγ subunits. KCTDs associate with the receptor by forming an asymmetric pentameric ring around a region of the receptor carboxy-terminal tail, while a second KCTD domain, H1, engages in a symmetric interaction with five copies of Gßγ in which the G-protein subunits also interact directly with one another. We further show that KCTD binding to Gßγ is highly cooperative, defining a model in which KCTD proteins cooperatively strip G proteins from GIRK channels to induce rapid desensitization following receptor activation. These results provide a framework for understanding the molecular basis for the precise temporal control of GABAB signalling by KCTD proteins.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/química , Proteínas do Tecido Nervoso/química , Proteínas/química , Receptores de GABA-B/química , Receptores de GABA-B/metabolismo , Transdução de Sinais , Cristalografia por Raios X , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/química , Canais de Potássio Corretores do Fluxo de Internalização Acoplados a Proteínas G/metabolismo , Subunidades beta da Proteína de Ligação ao GTP/química , Subunidades beta da Proteína de Ligação ao GTP/metabolismo , Subunidades beta da Proteína de Ligação ao GTP/ultraestrutura , Subunidades gama da Proteína de Ligação ao GTP/química , Subunidades gama da Proteína de Ligação ao GTP/metabolismo , Subunidades gama da Proteína de Ligação ao GTP/ultraestrutura , Humanos , Microscopia Eletrônica , Modelos Biológicos , Modelos Moleculares , Proteínas do Tecido Nervoso/ultraestrutura , Ligação Proteica , Domínios Proteicos , Proteínas/metabolismo , Proteínas/ultraestrutura , Receptores de GABA-B/ultraestrutura
8.
J Biol Chem ; 294(13): 5181-5197, 2019 03 29.
Artigo em Inglês | MEDLINE | ID: mdl-30804214

RESUMO

Cryogenic electron microscopy (cryo-EM) enables structure determination of macromolecular objects and their assemblies. Although the techniques have been developing for nearly four decades, they have gained widespread attention in recent years due to technical advances on numerous fronts, enabling traditional microscopists to break into the world of molecular structural biology. Many samples can now be routinely analyzed at near-atomic resolution using standard imaging and image analysis techniques. However, numerous challenges to conventional workflows remain, and continued technical advances open entirely novel opportunities for discovery and exploration. Here, I will review some of the main methods surrounding cryo-EM with an emphasis specifically on single-particle analysis, and I will highlight challenges, open questions, and opportunities for methodology development.


Assuntos
Microscopia Crioeletrônica/métodos , Imagem Tridimensional/métodos , Proteínas/ultraestrutura , Animais , Microscopia Crioeletrônica/instrumentação , Desenho de Equipamento , Humanos , Imagem Tridimensional/instrumentação , Conformação Proteica , Mapas de Interação de Proteínas , Proteínas/química , Proteínas/metabolismo
9.
Acta Crystallogr F Struct Biol Commun ; 75(Pt 1): 19-32, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-30605122

RESUMO

Single-particle analysis by electron microscopy is a well established technique for analyzing the three-dimensional structures of biological macromolecules. Besides its ability to produce high-resolution structures, it also provides insights into the dynamic behavior of the structures by elucidating their conformational variability. Here, the different image-processing methods currently available to study continuous conformational changes are reviewed.


Assuntos
Elétrons , Processamento de Imagem Assistida por Computador/estatística & dados numéricos , Imagem Tridimensional/estatística & dados numéricos , Substâncias Macromoleculares/ultraestrutura , Microscopia Eletrônica/métodos , Proteínas/ultraestrutura , Algoritmos , Humanos , Substâncias Macromoleculares/química , Microscopia Eletrônica/instrumentação , Conformação Molecular , Simulação de Dinâmica Molecular , Análise de Componente Principal , Proteínas/química , Termodinâmica
10.
Chem Soc Rev ; 47(24): 9069-9105, 2018 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-30452046

RESUMO

Nature has evolved an optimal synthetic factory in the form of translational and posttranslational processes by which millions of proteins with defined primary sequences and 3D structures can be built. Nature's toolkit gives rise to protein building blocks, which dictates their spatial arrangement to form functional protein nanostructures that serve a myriad of functions in cells, ranging from biocatalysis, formation of structural networks, and regulation of biochemical processes, to sensing. With the advent of chemical tools for site-selective protein modifications and recombinant engineering, there is a rapid development to develop and apply synthetic methods for creating structurally defined, functional protein nanostructures for a broad range of applications in the fields of catalysis, materials and biomedical sciences. In this review, design principles and structural features for achieving and characterizing functional protein nanostructures by synthetic approaches are summarized. The synthetic customization of protein building blocks, the design and introduction of recognition units and linkers and subsequent assembly into structurally defined protein architectures are discussed herein. Key examples of these supramolecular protein nanostructures, their unique functions and resultant impact for biomedical applications are highlighted.


Assuntos
Nanoestruturas/química , Nanotecnologia/métodos , Proteínas/química , Animais , Catálise , Técnicas de Química Sintética/métodos , Humanos , Modelos Moleculares , Nanoestruturas/ultraestrutura , Conformação Proteica , Engenharia de Proteínas/métodos , Proteínas/síntese química , Proteínas/genética , Proteínas/ultraestrutura
11.
Nat Protoc ; 13(12): 2890-2907, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30446750

RESUMO

Fast, high-resolution mapping of heterogeneous interfaces with a wide elastic modulus range is a major goal of atomic force microscopy (AFM). This goal becomes more challenging when the nanomechanical mapping involves biomolecules in their native environment. Over the years, several AFM-based methods have been developed to address this goal. However, none of these methods combine sub-nanometer spatial resolution, quantitative accuracy, fast data acquisition speed, wide elastic modulus range and operation in physiological solutions. Here, we present detailed procedures for generating high-resolution maps of the elastic properties of biomolecules and polymers using bimodal AFM. This requires the simultaneous excitation of the first two eigenmodes of the cantilever. An amplitude modulation (AM) feedback acting on the first mode controls the tip-sample distance, and a frequency modulation (FM) feedback acts on the second mode. The method is fast because the elastic modulus, deformation and topography images are obtained simultaneously. The method is efficient because only a single data point per pixel is needed to generate the aforementioned images. The main stages of the bimodal imaging are sample preparation, calibration of the instrument, tuning of the microscope and generation of the nanomechanical maps. In addition, with knowledge of the deformation, bimodal AFM enables reconstruction of the true topography of the surface. It takes ~9 h to complete the whole procedure.


Assuntos
Técnicas de Imagem por Elasticidade/métodos , Elasticidade , Microscopia de Força Atômica/métodos , Polímeros/química , Proteínas/química , Animais , Materiais Biocompatíveis/química , Fenômenos Biomecânicos , Técnicas de Imagem por Elasticidade/economia , Técnicas de Imagem por Elasticidade/instrumentação , Desenho de Equipamento , Halobacterium salinarum/química , Halobacterium salinarum/ultraestrutura , Humanos , Microscopia de Força Atômica/economia , Microscopia de Força Atômica/instrumentação , Modelos Moleculares , Complexo de Endopeptidases do Proteassoma/química , Complexo de Endopeptidases do Proteassoma/ultraestrutura , Proteínas/ultraestrutura , Membrana Purpúrea/química , Membrana Purpúrea/ultraestrutura , Fatores de Tempo
13.
J Proteome Res ; 17(11): 3614-3627, 2018 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-30222357

RESUMO

Over the past decade, a suite of new mass-spectrometry-based proteomics methods has been developed that now enables the conformational properties of proteins and protein-ligand complexes to be studied in complex biological mixtures, from cell lysates to intact cells. Highlighted here are seven of the techniques in this new toolbox. These techniques include chemical cross-linking (XL-MS), hydroxyl radical footprinting (HRF), Drug Affinity Responsive Target Stability (DARTS), Limited Proteolysis (LiP), Pulse Proteolysis (PP), Stability of Proteins from Rates of Oxidation (SPROX), and Thermal Proteome Profiling (TPP). The above techniques all rely on conventional bottom-up proteomics strategies for peptide sequencing and protein identification. However, they have required the development of unconventional proteomic data analysis strategies. Discussed here are the current technical challenges associated with these different data analysis strategies as well as the relative analytical capabilities of the different techniques. The new biophysical capabilities that the above techniques bring to bear on proteomic research are also highlighted in the context of several different application areas in which these techniques have been used, including the study of protein ligand binding interactions (e.g., protein target discovery studies and protein interaction network analyses) and the characterization of biological states.


Assuntos
Espectrometria de Massas/métodos , Processamento de Proteína Pós-Traducional , Proteínas/química , Proteoma/química , Proteômica/tendências , Animais , Reagentes para Ligações Cruzadas/química , Bases de Dados de Proteínas , Medição da Troca de Deutério/métodos , Humanos , Marcação por Isótopo/métodos , Ligantes , Espectrometria de Massas/instrumentação , Ligação Proteica , Dobramento de Proteína , Estabilidade Proteica , Proteínas/metabolismo , Proteínas/ultraestrutura , Proteólise , Proteoma/ultraestrutura , Proteômica/instrumentação , Proteômica/métodos , Análise de Sequência de Proteína/instrumentação , Análise de Sequência de Proteína/métodos , Análise de Sequência de Proteína/estatística & dados numéricos , Termodinâmica
14.
Cell Chem Biol ; 25(11): 1318-1325, 2018 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-30100349

RESUMO

We present a perspective of our view of the application of cryoelectron microscopy (cryo-EM) to structure-based drug design (SBDD). We discuss the basic needs and requirements for SBDD, the current state of cryo-EM, and the challenges that need to be overcome for this technique to reach its full potential in facilitating the process of drug discovery.


Assuntos
Microscopia Crioeletrônica/instrumentação , Desenho de Drogas , Descoberta de Drogas/instrumentação , Bibliotecas de Moléculas Pequenas/química , Animais , Microscopia Crioeletrônica/métodos , Descoberta de Drogas/métodos , Desenho de Equipamento , Humanos , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica , Proteínas/química , Proteínas/metabolismo , Proteínas/ultraestrutura , Bibliotecas de Moléculas Pequenas/farmacologia
15.
J Struct Biol ; 204(3): 564-571, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30144506

RESUMO

We introduce a new method for assessing resolvability of structural features in density maps from Cryo-Electron Microscopy (Cryo-EM) using fitted or derived models. It calculates Z-scores for secondary structure elements (SSEs) and side chains. Z-scores capture how much larger the cross-correlation score (CCS) is for atoms in such features at their placed locations compared to the CCS at displaced positions. Z-scores are larger when the structural features are well-resolved, as confirmed by visual analysis. This method was applied to all 66 maps submitted to the 2015/2016 EMDB map challenge. For each map, the fitted model provided by the map committee was used in this assessment. The average Z-scores for each map and fitted model correlate moderately well with reported map resolutions (r2 = 0.45 for SSE Z-scores and r2 = 0.56 for side chain Z-scores). Rankings of the submitted maps based on average Z-scores seem to more closely agree with visual analysis. Z-scores can also be used to pinpoint which parts of a model are well-resolved in a map, and which parts of the model may need further fitting or refinement to make the model better match the density.


Assuntos
Microscopia Crioeletrônica/métodos , Conformação Proteica , Estrutura Secundária de Proteína , Proteínas/química , Modelos Moleculares , Complexo de Endopeptidases do Proteassoma/química , Complexo de Endopeptidases do Proteassoma/ultraestrutura , Proteínas/ultraestrutura
16.
PLoS One ; 13(7): e0198854, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29975698

RESUMO

In this paper, we describe SAFlex (Structural Alphabet Flexibility), an extension of an existing structural alphabet (HMM-SA), to better explore increasing protein three dimensional structure information by encoding conformations of proteins in case of missing residues or uncertainties. An SA aims to reduce three dimensional conformations of proteins as well as their analysis and comparison complexity by simplifying any conformation in a series of structural letters. Our methodology presents several novelties. Firstly, it can account for the encoding uncertainty by providing a wide range of encoding options: the maximum a posteriori, the marginal posterior distribution, and the effective number of letters at each given position. Secondly, our new algorithm deals with the missing data in the protein structure files (concerning more than 75% of the proteins from the Protein Data Bank) in a rigorous probabilistic framework. Thirdly, SAFlex is able to encode and to build a consensus encoding from different replicates of a single protein such as several homomer chains. This allows localizing structural differences between different chains and detecting structural variability, which is essential for protein flexibility identification. These improvements are illustrated on different proteins, such as the crystal structure of an eukaryotic small heat shock protein. They are promising to explore increasing protein redundancy data and obtain useful quantification of their flexibility.


Assuntos
Sequência de Aminoácidos , Modelos Moleculares , Conformação Proteica , Proteínas/ultraestrutura , Algoritmos , Bases de Dados de Proteínas , Cadeias de Markov , Conformação Molecular , Proteínas/química
17.
J Struct Biol ; 204(1): 96-108, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30017700

RESUMO

An evaluation system and a web infrastructure were developed for the second cryo-EM model challenge. The evaluation system includes tools to validate stereo-chemical plausibility of submitted models, check their fit to the corresponding density maps, estimate their overall and per-residue accuracy, and assess their similarity to reference cryo-EM or X-ray structures as well as other models submitted in this challenge. The web infrastructure provides a convenient interface for analyzing models at different levels of detail. It includes interactively sortable tables of evaluation scores for different subsets of models and different sublevels of structure organization, and a suite of visualization tools facilitating model analysis. The results are publicly accessible at http://model-compare.emdatabank.org.


Assuntos
Microscopia Crioeletrônica/métodos , Proteínas/ultraestrutura , Modelos Moleculares , Conformação Proteica
18.
J Struct Biol ; 203(3): 281-287, 2018 09.
Artigo em Inglês | MEDLINE | ID: mdl-29879486

RESUMO

Coiled coils are well described as powerful oligomerization motifs and exhibit a large diversity of functions, including gene regulation, cell division, membrane fusion and drug extrusion. The archaea S-layer originated right-handed coiled coil -RHCC-NT- is characterized by extreme stability and is free of cysteine and histidine moieties. In the current study, we have followed a multidisciplinary approach to investigate the capacity of RHCC-NT to bind a variety of ionic complex metal ions. At the outside of the RHCC-NT, one mercury ion forms an electrostatic interaction with the S-methyl moiety of the single methionine residue present in each coil. We demonstrate that RHCC-NT is reducing and incorporating metallic mercury in the large-sized interior cavities which are lined up along the tetrameric channel.


Assuntos
Archaea/química , Nanotubos/química , Conformação Proteica , Proteínas/química , Mercúrio , Modelos Moleculares , Ligação Proteica , Domínios Proteicos , Estrutura Secundária de Proteína , Proteínas/ultraestrutura , Eletricidade Estática
19.
Methods Mol Biol ; 1814: 287-296, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29956239

RESUMO

High-resolution image acquisition and structure determination by cryo-electron microscopy is becoming increasingly streamlined. Preparing electron-microscopy grids of suitable quality remains, however, a critical bottleneck. Strategies to achieve particle monodispersity, optimal sample concentration and suitable ice thickness can vary from specimen to specimen. In this book chapter we describe our protocols for negative-stain grid and cryo-grid preparation, which we apply to studying protein-nucleic acid complexes.


Assuntos
Microscopia Crioeletrônica/métodos , Congelamento , Ácidos Nucleicos/ultraestrutura , Proteínas/ultraestrutura , Carbono/química , Coloração Negativa , Soluções
20.
J Chem Inf Model ; 58(6): 1303-1311, 2018 06 25.
Artigo em Inglês | MEDLINE | ID: mdl-29782796

RESUMO

As a relatively new technology to solve the three-dimensional (3D) structure of a protein or protein complex, single-particle reconstruction (SPR) of cryogenic electron microscopy (cryo-EM) images shows much superiority and is in a rapidly developing stage. Resolution measurement in SPR, which evaluates the quality of a reconstructed 3D density map, plays a critical role in promoting methodology development of SPR and structural biology. Because there is no benchmark map in the generation of a new structure, how to realize the resolution estimation of a new map is still an open problem. Existing approaches try to generate a hypothetical benchmark map by reconstructing two 3D models from two halves of the original 2D images for cross-reference, which may result in a premature estimation with a half-data model. In this paper, we report a new self-reference-based resolution estimation protocol, called SRes, that requires only a single reconstructed 3D map. The core idea of SRes is to perform a multiscale spectral analysis (MSSA) on the map through multiple size-variable masks segmenting the map. The MSSA-derived multiscale spectral signal-to-noise ratios (mSSNRs) reveal that their corresponding estimated resolutions will show a cliff jump phenomenon, indicating a significant change in the SSNR properties. The critical point on the cliff borderline is demonstrated to be the right estimator for the resolution of the map.


Assuntos
Microscopia Crioeletrônica/métodos , Imagem Tridimensional/métodos , Proteínas/ultraestrutura , Algoritmos , Modelos Moleculares , Conformação Proteica , Proteínas/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA