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1.
Arkh Patol ; 85(5): 73-76, 2023.
Artigo em Russo | MEDLINE | ID: mdl-37814854

RESUMO

Dmitry Egorovich Min is an outstanding pathologist, forensic physician and hygienist of the Russian Empire, a prominent public figure, professor and vice-rector of the Imperial Moscow University, an outstanding poet-translator and one of the founders of the Russian school of forensic medicine. This article discusses the biography of D.E. Min, his merits and accomplishments in labor and creative activity.


Assuntos
Médicos , Humanos , Moscou , Federação Russa
2.
Photosynth Res ; 153(3): 157-162, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35838829

RESUMO

Although there is an extensive literature on the properties and possible electron transfer pathways of cytochrome b-559, which is a prominent subunit of the multi-subunit photosystem II complex which functions in oxygenic photosynthesis, there is presently no consensus on the function of b-559 in the photosynthetic electron transport chain. The inability in earlier times to define a redox-linked function of this cytochrome was, to a large extent, a consequence of an absence of biochemical and structure information to complement an extensive array of spectrophotometric studies of the cytochrome in situ. Based on the location of hetero-dimeric b-559 in the photosystem II reaction center complex, derived from crystal crystallographic structure analysis, and the absence of a necessary redox function for the cytochrome in PSII, it is proposed that the main function of cytochrome b-559 is linked to its role as a structure component in the PSII reaction center complex. This function resides in the association of b-559 through its heme histidine residues in the trans-membrane domains of the PsbE and PsbF subunits of the PSII reaction center. These subunits, along with PsbJ, are inferred, from the analysis of structure, to define the intra-membrane portal in the PSII reaction center for plastoquinol (PQH2) export which, through the PSII complex, provides the redox link to the cytochrome b6f complex in the electron transfer chain.


Assuntos
Complexo Citocromos b6f , Complexo de Proteína do Fotossistema II , Grupo dos Citocromos b , Complexo Citocromos b6f/metabolismo , Citocromos b/metabolismo , Transporte de Elétrons , Heme/metabolismo , Histidina/metabolismo , Oxirredução , Oxigênio/metabolismo , Fotossíntese , Complexo de Proteína do Fotossistema II/metabolismo
3.
Artigo em Russo | MEDLINE | ID: mdl-35904293

RESUMO

AIM OF THE STUDY: To investigate the efficacy and safety of non-immunogenic staphylokinase (NS) compared with alteplase (A) in patients with acute ischemic stroke (AIS) within 4.5 h after symptom onset. MATERIAL AND METHODS: 336 patients with IS within 4.5 h after symptom onset were included in a randomized, open-label, multicenter, parallel-group, non-inferiority comparative trial of NS vs A (168 patients in each group). NS was administered as an intravenous bolus in a dose of 10 mg, regardless of body weight, over 10 s, A was administered as a bolus infusion in a dose of 0.9 mg/kg, maximum 90 mg over 1 hour. The primary efficacy endpoint was a favorable outcome, defined as a modified Rankin scale (mRS) score of 0-1 on day 90. Safety endpoints included all-cause mortality on day 90, symptomatic intracranial haemorrhage, and other serious adverse events (SAEs). RESULTS: At day 90, 84 (50%) patients reached the primary endpoint (mRS 0-1) in the NS group, 68 (41%) patients - in the A group (p=0.10, OR=1.47, 95% CI=0.93-2.32). The difference between groups NS and A was 9.5% (95% CI= -1.7-20.7) and the lower limit of the 95% CI did not cross the margin of non-inferiority (pnon-inferiority<0.0001). There were no significant differences in the frequency of deaths between the groups: on day 90, 17 (10%) patients in the NS group and 24 (14%) in the A group had died (p=0.32). There was a trend towards significant differences in the frequency of symptomatic intracranial haemorrhage: NS group - 5 (3%) patients, A group - 13 (8%) patients (p=0.087, OR=0.37, 95% CI=0.1-1.13). There were significant differences in the number of patients with SAEs: in the NS group - 22 (13%) patients, in the A group - 37 (22%) patients (p=0.044, OR=0.53, 95% CI=0.28-0.98). CONCLUSION: The presented results of the FRIDA trial are the first in the world to use a drug based on NS in patients with IS. It has been shown that a single bolus (within 10 s) administration of NS at a standard dose of 10 mg, regardless of body weight, allows to conduct fast, effective and safe thrombolytic therapy in patients with IS within 4.5 h after symptom onset. In further clinical tials of NS, it is planned to expand the therapeutic window beyond 4.5 h after symptom onset in patients with IS.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Metaloendopeptidases , Acidente Vascular Cerebral , Peso Corporal , Isquemia Encefálica/complicações , Isquemia Encefálica/tratamento farmacológico , Fibrinolíticos/uso terapêutico , Humanos , Hemorragias Intracranianas/induzido quimicamente , Hemorragias Intracranianas/complicações , Metaloendopeptidases/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/etiologia , Terapia Trombolítica , Resultado do Tratamento
4.
Med Leg J ; 89(3): 193-198, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34225527

RESUMO

Worldwide advances in computer techniques are not yet recognised in the practice of forensic medicine. A promising application is their use in making a three-dimensional reconstruction of the crime scene. This study analyses this technique in a homicide by firearm. Queries regarding the direction and number of shots, position of the victim inside the car when shot at and presence of the accused at the crime scene were answered by a scientific model. Similar reconstruction of the scene, nailing the accused in a heinous crime, has not previously been reported as a study or a case. The paper anticipates impetus to the growth of literature in criminology and forensic sciences. It will also expedite the delivery of justice based on scientific evidence in controversial causes of death.


Assuntos
Armas de Fogo , Homicídio , Computadores , Ciências Forenses , Humanos , Imageamento Tridimensional
5.
Angiol Sosud Khir ; 25(1): 32-38, 2019.
Artigo em Russo | MEDLINE | ID: mdl-30994605

RESUMO

Analysed herein are one-year results of formation of arteriovenous fistulas in 109 patients with end-stage chronic renal failure, as well as therapeutic decision-making after angiosurgical counselling of 144 patients presenting with 'problem' permanent vascular accesses. The counselling and formation of arteriovenous fistulas were carried out in conditions of interdepartmental collaboration between outpatient centres dealing with haemodialysis and vascular surgeons specialized in ultrasound mapping of peripheral vessels and performing different variants of arteriovenous fistulas. The angiosurgical care was as close to the patient as possible. Of the 109 operated patients, primary arteriovenous fistulas were made in 46 (42.2%) cases, secondary AVF - in 27 (24.8%) cases, and reconstruction of AVF - in 36 (33.0%) cases. Of the 144 patients with 'problem' permanent vascular assesses, correction of arteriovenous fistulas turned out impossible in 13 (9.1%). In the remaining 131 (90.9%) patients there was a possibility of different variants of open reconstruction of arteriovenous fistulas or performing angioplasty. Active policy of vascular surgeons in interdepartmental collaboration with nephrologists made it possible to bridge over the difficulties of patients routing which resulted in reduction of the terms of formation of arteriovenous fistulas by 2 months. Preventive arteriovenous fistulas were carried out in 17.4% of cases of primary permanent vascular assesses. During a year after formation of permanent vascular accesses, the number of patients with vascular catheters in ambulatory centres decreased from 22 to 17%. These positive changes in organization of the dialysis treatment made it possible to reduce the risks of infectious complications, to obtain adequate blood flow characteristics for haemodialysis procedures, as well as to decrease financial expenses and labour costs for AVF care.


Assuntos
Fístula Arteriovenosa , Derivação Arteriovenosa Cirúrgica , Falência Renal Crônica , Cirurgiões , Humanos , Diálise Renal , Grau de Desobstrução Vascular
6.
Sud Med Ekspert ; 62(1): 50-55, 2019.
Artigo em Russo | MEDLINE | ID: mdl-30724895

RESUMO

The present review of the literature publications concerns the problem of sudden death (SD) among the young persons under effect of the different forms of physical loads. The statistical data on the frequency of sudden death are presented together with information about risk factors of SD, the morphological substrates and structural changes that promote death coming. The cases of sudden death among the young persons associated with the amateur sports activities and the professional sport of records are presented. The role of physical exercises and psycho-emotional stresses in the development of the terminal processes is considered with special reference to the risk factors and genetic predisposition to sudden cardiac death, largely among male athletes. The questions of sudden death in connection with cardiac pathologies as its main causes are discussed.


Assuntos
Atletas , Morte Súbita Cardíaca/etiologia , Esportes , Predisposição Genética para Doença , Coração , Humanos , Masculino , Fatores de Risco
7.
Biochem J ; 475(23): 3903-3915, 2018 12 12.
Artigo em Inglês | MEDLINE | ID: mdl-30541793

RESUMO

Current problems in the understanding of colicin import across the Escherichia coli outer membrane (OM), involving a range of cytotoxic mechanisms, are discussed: (I) Crystal structure analysis of colicin E3 (RNAase) with bound OM vitamin B12 receptor, BtuB, and of the N-terminal translocation (T) domain of E3 and E9 (DNAase) inserted into the OM OmpF porin, provide details of the initial interaction of the colicin central receptor (R)- and N-terminal T-domain with OM receptors/translocators. (II) Features of the translocon include: (a) high-affinity (Kd ≈ 10-9 M) binding of the E3 receptor-binding R-domain E3 to BtuB; (b) insertion of disordered colicin N-terminal domain into the OmpF trimer; (c) binding of the N-terminus, documented for colicin E9, to the TolB protein on the periplasmic side of OmpF. Reinsertion of the colicin N-terminus into the second of the three pores in OmpF implies a colicin anchor site on the periplasmic side of OmpF. (III) Studies on the insertion of nuclease colicins into the cytoplasmic compartment imply that translocation proceeds via the C-terminal catalytic domain, proposed here to insert through the unoccupied third pore of the OmpF trimer, consistent with in vitro occlusion of OmpF channels by the isolated E3 C-terminal domain. (IV) Discussion of channel-forming colicins focuses mainly on colicin E1 for which BtuB is receptor and the OM TolC protein the proposed translocator. The ability of TolC, part of a multidrug efflux pump, for which there is no precedent for an import function, to provide a trans-periplasmic import pathway for colicin E1, is questioned on the basis of an unfavorable hairpin conformation of colicin N-terminal peptides inserted into TolC.


Assuntos
Membrana Celular/metabolismo , Colicinas/metabolismo , Proteínas de Escherichia coli/metabolismo , Escherichia coli/metabolismo , Proteínas da Membrana Bacteriana Externa/química , Proteínas da Membrana Bacteriana Externa/metabolismo , Colicinas/química , Cristalografia por Raios X , Proteínas de Escherichia coli/química , Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Modelos Moleculares , Ligação Proteica , Conformação Proteica , Transporte Proteico
8.
Clin Genet ; 94(5): 445-449, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29968299

RESUMO

As the susceptibility of humans to xenobiotics often depends on genetic factors, we assumed that ADH1B and ALDH2 genetic variants may affect susceptibility to the acute methanol exposure. To evaluate the role of genetic variants of enzymes involved in methanol catabolism in humans, we analysed ADH1B (rs1229984) and ALDH2 (rs441) polymorphisms in 50 adults who survived acute methanol poisoning, 246 individuals with alcoholic liver cirrhosis, and in 545 healthy controls. GG homozygotes of ADH1B were more common among methanol-poisoned patients (98%) and among patients with alcoholic liver cirrhosis (98%) than among healthy controls (90%) (P = 0.08 and < 0.001, respectively). Minor C allele carriers of the ALDH2 were significantly more common among methanol-poisoned persons (46%) than among patients with alcoholic liver cirrhosis or healthy controls (31% in both groups, P < 0.05 and 0.025, respectively); the odds ratios were 1.89 (95% CI 1.02-3.52) and 1.94 (1.08-3.48), respectively. As there was a substantial amount of subjects with alcohol abuse between both groups of patients, ADH1B is unlikely to affect the susceptibility to methanol poisoning. By contrast, the genetic variant of the ALDH2 enzyme seems to specifically affect the susceptibility to methanol in acutely exposed humans and potentially plays a role in the outcome of methanol poisoning.


Assuntos
Aldeído-Desidrogenase Mitocondrial/genética , Metanol/efeitos adversos , Variantes Farmacogenômicos , Polimorfismo Genético , Adulto , Idoso , Alcoolismo/complicações , Alcoolismo/etiologia , Alelos , Feminino , Genótipo , Humanos , Cirrose Hepática/etiologia , Cirrose Hepática/patologia , Masculino , Metanol/intoxicação , Pessoa de Meia-Idade , Razão de Chances , Polimorfismo de Nucleotídeo Único , Adulto Jovem
9.
Alcohol ; 59: 27-35, 2017 03.
Artigo em Inglês | MEDLINE | ID: mdl-28262185

RESUMO

Methanol poisoning leads to lesions in the basal ganglia and subcortical white matter, as well as to demyelination and atrophy of the optic nerve. However, information regarding cognitive deficits in a large methanol sample is lacking. The principal aim of the present study was to identify the cognitive sequelae of methanol poisoning and their morphological correlates. A sample of 50 patients (METH; age 48 ± 13 years), 3-8 months after methanol poisoning, and 57 control subjects (CS; age 49 ± 13 years) were administered a neuropsychological battery. Forty-six patients were followed in 2 years' perspective. Patients additionally underwent 1.5T magnetic resonance imaging (MRI). Three biochemical and toxicological metabolic markers and a questionnaire regarding alcohol abuse facilitated the classification of 24 patients with methanol poisoning without alcohol abuse (METHna) and 22 patients with methanol poisoning and alcohol abuse (METHa). All groups were compared to a control group of similar size, and matched for age, education, premorbid intelligence level, global cognitive performance, and level of depressive symptoms. Using hierarchical multiple regression we found significant differences between METH and CS, especially in executive and memory domains. METHa showed a similar pattern of cognitive impairment with generally more severe executive dysfunction. Moreover, all METH patients with extensive involvement on brain MRI (lesions in ≥2 anatomical regions) had a more severe cognitive impairment. From a longitudinal perspective, we did not find any changes in their cognitive functioning after 2 years' follow-up. Our findings suggest that methanol poisoning is associated with executive dysfunction and explicit memory impairment, supposedly due to basal ganglia dysfunction and disruption of frontostriatal circuitry proportional to the number of brain lesions, and that these changes are persistent after 2 years' follow-up.


Assuntos
Transtornos Cognitivos/induzido quimicamente , Transtornos Cognitivos/diagnóstico por imagem , Função Executiva , Transtornos da Memória/induzido quimicamente , Transtornos da Memória/diagnóstico por imagem , Metanol/intoxicação , Adulto , Idoso , Transtornos Cognitivos/psicologia , Estudos Transversais , Feminino , Seguimentos , Humanos , Estudos Longitudinais , Masculino , Transtornos da Memória/psicologia , Pessoa de Meia-Idade , Testes Neuropsicológicos , Fatores de Tempo
10.
J Phys Chem B ; 121(5): 975-983, 2017 02 09.
Artigo em Inglês | MEDLINE | ID: mdl-28032998

RESUMO

The intramembrane cytochrome bc1 complex of the photosynthetic bacterium Rhodobacter capsulatus and the cytochrome b6f complex, which functions in oxygenic photosynthesis, utilize two pairs of b-hemes in a symmetric dimer to accomplish proton-coupled electron transfer. The transmembrane electron transfer pathway in each complex was identified through the novel use of heme Soret band excitonic circular dichroism (CD) spectra, for which the responsible heme-heme interactions were determined from crystal structures. Kinetics of heme reduction and CD amplitude change were measured simultaneously. For bc1, in which the redox potentials of the transmembrane heme pair are separated by 160 mV, heme reduction occurs preferentially to the higher-potential intermonomer heme pair on the electronegative (n) side of the complex. This contrasts with the b6f complex, where the redox potential difference between transmembrane intramonomer p- and n-side hemes is substantially smaller and the n-p pair is preferentially reduced. Limits on the dielectric constant between intramonomer hemes were calculated from the interheme distance and the redox potential difference, ΔEm. The difference in preferred reduction pathway is a consequence of the larger ΔEm between n- and p-side hemes in bc1, which favors the reduction of n-side hemes and cannot be offset by decreased repulsive Coulombic interactions between intramonomer hemes.


Assuntos
Complexos de Coordenação/química , Citocromos/metabolismo , Transporte de Elétrons , Heme , Animais , Dicroísmo Circular , Cristalografia por Raios X , Citocromos/química , Complexo III da Cadeia de Transporte de Elétrons/química , Heme/química , Humanos , Cinética , Membranas/metabolismo , Modelos Moleculares , Oxirredução , Transdução de Sinais
11.
Vopr Onkol ; 62(4): 535-41, 2016.
Artigo em Russo | MEDLINE | ID: mdl-30475569

RESUMO

The article presents a review of references on causes of sudden death of persons suffering from oncological diseases. The paper describes the main mechanisms of sudden death of persons with cancer who are subjected to forensic-medical research. Data on the structure of sudden death for the last 10 years are demonstrated. The authors have identified the increase of a number of sudden deaths in the group with oncological pathology 2. 2 times more in comparison with 2005. There are showed peculiarities of forensic-medical diagnostics of reasons of sudden death in cancer.


Assuntos
Morte Súbita , Patologia Legal , Neoplasias/mortalidade , Autopsia , Causas de Morte , Feminino , Humanos , Masculino , Neoplasias/fisiopatologia
12.
Occup Environ Med ; 73(2): 110-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26644454

RESUMO

OBJECTIVE: The use of nanotechnology is growing enormously and occupational physicians have an increasing interest in evaluating potential hazards and finding biomarkers of effect in workers exposed to nanoparticles. METHODS: A study was carried out with 36 workers exposed to (nano)TiO2 pigment and 45 controls. Condensate (EBC) titanium and markers of oxidation of nucleic acids (including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU)) and proteins (such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr) and 3-nitrotyrosine (3-NOTyr)) were analysed from samples of their exhaled breath. RESULTS: In the production workshops, the median total mass 2012 and 2013 TiO2 concentrations were 0.65 and 0.40 mg/m(3), respectively. The median numbers of concentrations measured by the scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) were 1.98 × 10(4) and 2.32 × 10(4) particles/cm(3), respectively; and about 80% of those particles were smaller than 100 nm in diameter. In the research workspace, lower aerosol concentrations (0.16 mg/m(3) and 1.32 × 10(4) particles/cm(3)) were found. Titanium in the EBC was significantly higher in production workers (p<0.001) than in research workers and unexposed controls. Accordingly, most EBC oxidative stress markers, including in the preshift samples, were higher in production workers than in the two other groups. Multiple regression analysis confirmed an association between the production of TiO2 and the levels of studied biomarkers. CONCLUSIONS: The concentration of titanium in EBC may serve as a direct exposure marker in workers producing TiO2 pigment; the markers of oxidative stress reflect the local biological effect of (nano)TiO2 in the respiratory tract of the exposed workers.


Assuntos
Nanopartículas/efeitos adversos , Ácidos Nucleicos/metabolismo , Exposição Ocupacional/efeitos adversos , Estresse Oxidativo/efeitos dos fármacos , Material Particulado/efeitos adversos , Proteínas/metabolismo , Titânio/efeitos adversos , Adulto , Biomarcadores/metabolismo , Testes Respiratórios , Dano ao DNA , Humanos , Masculino , Pessoa de Meia-Idade , Oxirredução , Tamanho da Partícula , Trabalho , Adulto Jovem
13.
Biofizika ; 60(6): 1146-50, 2015.
Artigo em Russo | MEDLINE | ID: mdl-26841509

RESUMO

Suppression of resistance in acute myeloid leukemia cells to TRAIL-induced apoptosis in multicellular aggregates, was studied using small molecule inhibitors of the activation of the transcription factor NF-kB - NF-k9 Activation Inhibitor IV and JSH-23 at non-toxic concentrations. NF-kB Activation Inhibitor IV and JSH-23 reduced resistance in the acute myeloid leukemia cells in multicellular aggregates to cytotoxic action of recombinant protein izTRAIL. It is shown that the use of these inhibitors decreased the phosphorylation of the RelA (p65) as a main marker activation of the transcription factor NF-kB. We discuss a possible reason for increasing resistance in acute myeloid leukemia cells to TRAIL-induced apoptosis in multicellular aggregates.


Assuntos
Leucemia Mieloide Aguda/tratamento farmacológico , NF-kappa B/antagonistas & inibidores , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Fator de Transcrição RelA/metabolismo , Apoptose/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Leucemia Mieloide Aguda/genética , Fenilenodiaminas/administração & dosagem , Fosforilação/efeitos dos fármacos , Agregados Proteicos/efeitos dos fármacos , Ligante Indutor de Apoptose Relacionado a TNF/administração & dosagem , Fator de Transcrição RelA/química , Ativação Transcricional/efeitos dos fármacos
14.
Biofizika ; 58(5): 904-9, 2013.
Artigo em Russo | MEDLINE | ID: mdl-25481960

RESUMO

According to the last results obtained by small-angle X-ray scattering and X-ray spectroscopy it was suggested that water within the nanometer scale represents a fluctuating mixture of clusters with tetrahedral structure and a subphase with partially broken hydrogen bonds whereas the nuclear configuration of the H20 molecule corresponds to single tetrahedral coordination. The basic reason of such structural partition is not clear until now. Here we show that it can be associated with the existence of two nuclear H2O spin-isomers which have different probability to be in one or another subphase. The para-molecule can transfer an excess of its rotational energy to the environment up to the complete stopping of rotation because its rotational quantum number J = 0 in the basic state. This property is favorable for the formation of clusters with closed H-bonds. Ortho-molecules with odd-numbered J states lack for this property and thus should be predominantly present in the surrounding with distorted bonds.


Assuntos
Isomerismo , Teoria Quântica , Água/química , Ligação de Hidrogênio , Análise Espectral
15.
Stomatologiia (Mosk) ; 91(3): 65-9, 2012.
Artigo em Russo | MEDLINE | ID: mdl-22968618

RESUMO

Simulation in 3D-model of skeletal forms of sagittal malocclusion revealed tendency in tonus' modification of muscles of mastication in formation of distal and mesial occlusion. It's shown that distal occlusion is characterized by hypotonic condition of muscles of mastication, except posterior fibers of temporal muscle. Mesial occlusion is characterized by complex combination of muscle tone with prevalence of hypotonic condition of anterior fibers of temporal muscle, superficial portion of masseter muscle and medial pterygoid muscle. We have detected that using of myofunctional devices in treatment of sagittal malocclusion, temporomandibular joint dysfunction promotes of tone increasing of muscles of mastication.


Assuntos
Má Oclusão/terapia , Mastigação , Modelos Anatômicos , Síndrome da Disfunção da Articulação Temporomandibular/terapia , Humanos , Má Oclusão/fisiopatologia , Músculo Masseter/fisiopatologia , Músculos Pterigoides/fisiopatologia , Músculo Temporal/fisiopatologia , Síndrome da Disfunção da Articulação Temporomandibular/fisiopatologia
16.
Voen Med Zh ; 333(2): 10-5, 2012 Feb.
Artigo em Russo | MEDLINE | ID: mdl-22558846

RESUMO

Some reasons preventing realization of a principle of vocational training of the medical personnel of health service BC the Russian Federation, including the expense of insufficient efficiency of planning of formation are considered in the article. Recommendations about working out of the personnel register are given.


Assuntos
Educação Médica/organização & administração , Educação Médica/normas , Medicina Militar , Educação Médica/legislação & jurisprudência , Feminino , Humanos , Masculino , Federação Russa
17.
Biofizika ; 57(6): 939-44, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23272574

RESUMO

Before a biochemical reaction begins to occur reagents need to recognize each other. To explain the recognition mechanism the "key-lock" hypothesis has been proposed at the end of the nineteenth century. Now it should be reconsidered since in the overwhelming majority of cases surface landscapes of the interacting molecules -- individually and in the complex -- do not coincide. The subsequent modifications of this hypothesis, for instance, the ligand-induced adjustment, were unable to predict a degree of the partner affinity and alleviate decision-making in essential task as to the search for the new drug forms. Here we offer a concept according to which the approaching reagents recognize each other by their hydration shells. Such an approach is based on the existence of universal structural blocks in water skeleton of biomolecules. The mutual recognition occurs when hydration shells of reagents are structurally compatible. This statement is demonstrated by the example of the simplest biochemical reaction.


Assuntos
Estrutura Molecular , Água/química , Algoritmos , Fenômenos Químicos , Galactose/química , Glucose/química , Ligantes , Modelos Moleculares
18.
Biofizika ; 57(6): 1054-7, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23272587

RESUMO

The principles of searching and selection of the polymeric materials compatible with biological tissues are offered, based on structural features of the hydration shells of biopolymers.


Assuntos
Materiais Biocompatíveis/química , Estrutura Molecular , Polímeros/química , Água/química , Fractais , Humanos , Nanoestruturas/química
19.
Biofizika ; 57(6): 1041-53, 2012.
Artigo em Russo | MEDLINE | ID: mdl-23272586

RESUMO

Recently a model of local organization of water was experimentally justified, in which tetrahedrally coordinated water clusters of 1-2 nanometers arise and disappear in liquid composed of H2O molecules with partially broken hydrogen bonds [1, 2]. Here we show that the clusters can oscillate between two structural forms, of which one is common hexagonal ice Ih whereas another is formed of the modules participating in formation of hydration shells of biomolecules. It is suggested that such self-oscillations are responsible for observable fluctuations of various physical and chemical parameters of water.


Assuntos
DNA/química , Gelo , Proteínas/química , Água/química , Fenômenos Biofísicos , Ligação de Hidrogênio , Simulação de Dinâmica Molecular
20.
Methods ; 55(4): 415-20, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22079407

RESUMO

Studies on four membrane protein systems, which combine information derived from crystal structures and biophysical studies have emphasized, as a precursor to crystallization, demonstration of functional activity. These assays have relied on sensitive spectrophotometric, electrophysiological, and microbiological assays of activity to select purification procedures that lead to functional complexes and with greater likelihood to successful crystallization: (I), Hetero-oligomeric proteins involved in electron transport/proton translocation. (1) Crystal structures of the eight subunit hetero-oligomeric trans-membrane dimeric cytochrome b(6)f complex were obtained from cyanobacteria using a protocol that allowed an analysis of the structure and function of internal lipids at specific intra-membrane, intra-protein sites. Proteolysis and monomerization that inactivated the complex and prevented crystallization was minimized through the use of filamentous cyanobacterial strains that seem to have a different set of membrane-active proteases. (2) An NADPH-quinone oxido-reductase isolated from cyanobacteria contains an expanded set of 17 monotopic and polytopic hetero-subunits. (II) ß-Barrel outer membrane proteins (OMPs). High resolution structures of the vitamin B(12) binding protein, BtuB, solved in meso and in surfo, provide the best example of the differences in such structures that were anticipated in the first application of the lipid cubic phase to membrane proteins [1]. A structure of the complex of BtuB with the colicin E3 and E2 receptor binding domain established a "fishing pole" model for outer membrane receptor function in cellular import of nuclease colicins. (III) A modified faster purification procedure contributed to significantly improved resolution (1.83Å) of the universal porin, OmpF, the first membrane protein for which meaningful 3D crystals have been obtained [2]. A crystal structure of the N-terminal translocation domain of colicin E3 complexed to OmpF established the role of OmpF as an import channel for colicin nuclease cytotoxins. (IV) α-Synuclein, associated with the etiology of Parkinson's Disease, is an example of a protein, which is soluble and disordered in solution, but which can assume an ordered predominantly α-helical conformation upon binding to membranes. When subjected in its membrane-bound form to a trans-membrane electrical potential, α-synuclein can form voltage-gated ion channels. Summary of methods to assay functions/activities: (i) sensitive spectrophotometric assay to measure electron transfer activities; (ii) hydrophobic chromatography to deplete lipids, allowing reconstitution with specific lipids for studies on lipid-protein interactions; (iii) microbiological screen to assay high affinity binding of colicin receptor domains to Escherichia coli outer membrane receptors; (iv) electrophysiology/channel analysis (a) to select channel-occluding ligands for co-crystallization with ion channels of OmpF, and (b) to provide a unique description of voltage-gated ion channels of α-synuclein.


Assuntos
Proteínas da Membrana Bacteriana Externa/química , Complexo Citocromos b6f/química , Proteínas de Escherichia coli/química , Proteínas de Membrana Transportadoras/química , NADPH Desidrogenase/química , Porinas/química , alfa-Sinucleína/química , Cristalização , Cristalografia por Raios X , Cianobactérias/enzimologia , Ensaios Enzimáticos , Escherichia coli/enzimologia , Humanos , Modelos Moleculares , NADPH Desidrogenase/isolamento & purificação , Estrutura Secundária de Proteína , Estrutura Terciária de Proteína , Subunidades Proteicas/química
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