ПЕТЛИ NGF
А.В.ТАРАСЮК, Н.М.САЗОНОВА, И.О.ЛОГВИНОВ,
Т.А.АНТИПОВА, Т.А.ГУДАШЕВА
ФГБНУ «НИИ фармакологии имени В.В. Закусова»
tarasiuk86@gmail.com
РОССИЙСКАЯ ФЕДЕРАЦИЯ
Фактор роста нервов (NGF), первый из семейства нейротрофинов, со времени открытия в
начале 50-х годов XX века привлекает внимание как возможное средство лечения острых
нарушений мозгового кровообращения и ряда нейродегенеративных заболеваний. Применение
NGF в клинике ограничено серьезными побочными эффектами - гиперальгезией и потерей
веса, а также плохими фармакокинетическими свойствами. Поэтому ведется активный поиск
низкомолекулярных соединений, обладающих эффектами NGF, перспективными для
фармакотерапии, но свободных от недостатков полноразмерного белка.
Ранее [Gudasheva T.A. et al. / J. Biomed. Sci. 2015] был получен активный миметик NGF ГК-
2, сконструированный на основе наиболее экспонированной 4-й петли нейротрофина,
обладающий нейропротекторными свойствами. Для более детального изучения функций
нейротрофина NGF с помощью его низкомолекулярных миметиков были сконструированы и
исследованы миметики 3-й петли NGF.
Для дизайна новых миметиков был выбран бета-изгиб 3-й петли, содержащей остатки -
Ser73-Lys74-His75-Trp76-. В структуре миметика сохраняли аминокислотные остатки централь-
ного фрагмента бета-изгиба 3-й петли (-Lys74-His75-), боковые радикалы которых по геометри-
ческим данным могут наиболее глубоко проникать в зону связывания рецептора и наиболее
полно распознаваться. Периферийный остаток -Ser73- был заменен его биоизостером, остатком
гамма-оксимасляной кислоты, а остаток -Trp76- – амидной группой. Цели этих двух замен –
стабилизация конформации бета-изгиба, увеличение устойчивости соединения к действию
пептидаз, а также удешевление синтеза.
Так как NGF взаимодействует с рецептором в гомодимерной форме, для получения
соединения с агонистической активностью мы также получили гомодимерную форму из двух
миметиков бета-изгиба димеризовав их голова-к-голове с помощью гексаметилендиаминового
спейсера. Таким образом, был сконструирован димерный дипептидный миметик 3-й петли NGF
ГТС-115 - гексаметилендиамид бис-(N-гамма-оксибутирил-L-лизил-L-гистидина), а также его
ацетилсодержащий аналог - ГТС-113 - гексаметилендиамид бис-(N-ацетил-L-лизил-L-гистидина).
Пептиды ГТС-113 и ГТС-115 получали с использованием классических методов пептид-
ного синтеза в растворе. Использовали Z/Boc - стратегию защитных групп, наращивание пеп-
тидной цепи вели с N-конца, конденсацию аминокислотных остатков проводили методом
активированных N-оксисукцинимидных эфиров. Конденсацию N-защищенного дипептида с
гексаметилендиамином проводили азидным методом. Целевые соединения получали в виде
гидрохлоридов с выходами 46% и 43%.
С использованием культуры клеток НТ22 в условиях окислительного стресса, было
показано наличие у миметика ГТС-115 нейропротекторной активности в концентрациях от 10-5
до 10-7М. Ацетилсодержащий миметик ГТC-113 не проявил активности.
Полученные результаты позволяют сделать заключение о важной роли остатка серина
(Ser73) для проявления нейропротекторной активности миметиком 3-й петли нейротрофина
NGF ГТС-115.
Работа частично выполнена при поддержке Российского научного фонда (проект № 14-15-
00596).
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Qafqaz University 29-30 April 2016, Baku, Azerbaijan
USING Y CHROMOSOMAL HAPLOGROUPS IN GENETIC
ASSOCIATION STUDIES AND SUGGESTED IMPLICATIONS
Denis A. BAIRD
1
A. Mesut ERZURUMLUOGLU
2
1
School of Clinical Sciences, Musculoskeletal Research Unit,
Learning and Research Building, Southmead Hospital,
Bristol, UK.
2
Genetic Epidemiology Group,
Department of Health Sciences, University of Leicester,
Leicester, UK
denis.baird@bristol.ac.uk
Y chromosomal (Y-DNA) haplogroups are more widely used in population genetics than in
genetic epidemiology, although associations between Y-DNA haplogroups and several traits
(including cardio-metabolic traits) have been reported. In apparently homogeneous populations, there
is still Y-DNA haplogroup variation which will result from population history. Therefore, hidden
stratification and/or differential phenotypic effects by Y-DNA haplogroups could exist. To test this,
we hypothesised that stratifying individuals according to their Y-DNA haplogroups before testing
associations between autosomal SNPs and phenotypes will yield difference in association. For proof of
concept, we derived Y-DNA haplogroups from 6,537 males from two epidemiological cohorts,
ALSPAC (N=5,080, 816 Y-DNA SNPs) and 1958 Birth Cohort (N=1,457, 1,849 Y-DNA SNPs). For
illustration, we studied well-known associations between 32 SNPs and body mass index (BMI),
including associations involving FTO SNPs. Overall, no association was replicated in both cohorts
when Y-DNA haplogroups were considered and this suggests that, for BMI at least, there is little
evidence of differences in phenotype or gene association by Y-DNA structure. Further studies using
other traits, Phenome-wide association studies (PheWAS), haplogroups and/or autosomal SNPs are
required to test the generalisability of this approach.
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IMPORTANCE OF GENETIC STUDIES IN CONSANGUINEOUS
POPULATIONS FOR THE CHARACTERIZATION OF NOVEL
HUMAN GENE FUNCTIONS
A. Mesut ERZURUMLUOGLU
Genetic Epidemiology Group,
Department of Health Sciences, University of Leicester,
Leicester, UK
epmmee@my.bristol.ac.uk
Consanguineous offspring have elevated levels of homozygosity. Autozygous stretches within
their genome are likely toharbour loss of function (LoF) mutations which will lead to complete
inactivation or dysfunction of genes. Studyingconsanguineous offspring with clinical phenotypes has
been very useful for identifying disease causal mutations. However,at present, most of the genes in the
human genome have no disorder associated with them and/or have unknown function. Thisis
presumably mostly due to the fact that homozygous LoFvariants are not observed in outbred
populations which are themain focus of large sequencing projects. However, another reason may be
that many genes in the genome – even whencompletely “knocked out” – do not cause a distinct or
defined phenotype. In a recently published paper, I discussed the benefits and implicationsof studying
consanguineous populations, as opposed to the traditional approach of analysing a subset of
consanguineousfamilies or individuals with disease. I also suggested that studying consanguineous
populations “as a whole” can speed up thecharacterisation of novel gene functions as well as indicating
non-essential genes and/or regions in the human genome. Finally, I proposed designing a single
nucleotide variant (SNV) array with probes for all possible stop-gains (nonsense variants) in the
human genome (n≈ 4.5 million)and using it to screen highly consanguineous populations with a rich
gene pool (e.g. the population of Riyadh) to make the process more efficient.
Knockout studies in model organisms are well established and have hugely facilitated our
understanding of our own genome and the biological pathways which connect many of the twenty
thousand or so genes. However, where not backed up by human observational studies, animal knock-
outs can be misleading as the underlying mechanism may be different in the model organism or the
gene may have a different (or other acquired) function(s). Also some human genes lack homologues in
the commonly analysed model organisms (some may even have no homologues, also known as
‘orphan’ genes) which is another limitation of these gene knockout studies. Therefore candidate genes
derived from model organism ‘knockouts’ cannot be directly translated to a human model until the
same phenotype is also observed in humans. However, sampling randomly from a consanguineous
population will enable the identification of natural human knock-outs, enabling the identification of
house-keeping genes (i.e. when knocked out, are lethal before reaching puberty), non-essential genes
(i.e. when knocked out, do not cause any clinical outcomes early or late in life), genes which cause late
onset disorders (e.g. highly penetrant mutations in certain genes causing certain cancers) and genes
causing embryo loss - alongside the Mendelian (and monogenic forms of common) disease causal
ones. In this sense, studies of consanguineous populations can be used as examples of a ‘quasi-reverse
genetics’ study (QRG), with direction of study being ‘genotype to phenotype’, similar to the reverse
genetics studies carried out in model organisms. To put simply, which genes have been inactivated in a
consanguineous individual can be determined initially using whole-exome sequencing (WES) or
genotyping, then the short-term and long-term effects of the knockouts can be observed; if any.
Ultimately, findings from ‘complete knock-outs’ can have considerable implications at the
‘population’ level, and not just for the respective families/individuals (e.g. by facilitating useful drug
target identification, elucidating underlying biology of certain traits/diseases).
IV INTERNATIONAL SCIENTIFIC CONFERENCE OF YOUNG RESEARCHERS
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Qafqaz University 29-30 April 2016, Baku, Azerbaijan
PROCEEDINGS
SECTION I
NATURAL SCIENCES
Physics
Mathematics
Chemistry and Chemical Engineering
Biology
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PROCEEDINGS
SECTION I
NATURAL SCIENCES
Physics
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EXPERIMENTAL DATA INTERPRETATION FOR MOLECULAR
MODELING OF THE PROTEIN–DNA COMPLEXES STRUCTURE
G.A. ARMEEV, A.K. SHAYTAN
Lomonosov Moscow State University
armeev@molsim.org
RUSSIA
DNA is a linear molecule that carries most of the genetic information of organism. There are
several levels of DNA organisation since the eukaryotic genome in its fully unfolded form cannot fit
into a relatively compact nucleus. DNA storage and fine regulation of the cell genetic apparatus is
carried out at the level of individual nucleosomes. The structure of nucleosomes affects a number of
processes, such as DNA transcription, replication, and repair. Nucleosome structure is determined with
nearly atomic resolution by X-ray diffraction however it is difficult to study the higher levels of
chromatin organization by the usual methods of structural biology. In this account we discuss the
question of constructing three-dimensional models of DNA in complex with proteins using computer
modeling and indirect methods of studying the conformation of macromolecules. We discuss some
aspects of integrating such data into the process of constructing the molecular models of protein-DNA
complexes based on the geometric characteristics of DNA. We propose an algorithm for estimating
conformations of protein-DNA complexes based on the information about the local flexibility of DNA
and on the experimental data obtained by Forster resonance energy transfer (FRET) and hydroxyl
footprinting. Finally, we use this algorithm to predict the hypothetical configuration of DNA in a
nucleosome bound with histone H1.
To date, the nucleosome-H1 complex is not in the PDB data bank of three-dimensional protein
structures. However, the works in which the structure of this complex has been studied by nuclear
magnetic resonance are available. Histone H1, also known as the linker histone, forms a complex with
nucleo-somes that promotes a higher level of the DNA compaction. Providing such an impact on the
arrangement/ordering of DNA in the cell, histone H1 plays an important role in the regulation of gene
expression. Structural features of the interactions between the linker histone and nucleosome are still
unknown and their studies attract great interest.
To construct the model, we used the structure 1KX5 from the PDB data bank as the basis; linkers
were added to this structure in accordance with the sequence used in the FRET experiment. Based on
the footprinting data, we selected the DNA segments that are not bound to protein. After minimizing
the DNA geometry using the distance constraints obtained from the FRET data, an asymmetric
structure with a parallel arrangement of the DNA linker segments was obtained (Fig. 1). Very similar
models were obtained in, where the structure of chromatosomes was studied by hydroxyl footprinting
and electron microscopy. In the future, the resulting structure can be used as a target for the
macromolecular docking of histone H1.
The developed method makes it possible to create the geometry models of DNA in complex with
proteins using the molecular modeling based on the integration of the experimental data and the data
on the local rigidity of DNA. This method also enables us to obtain atomistic models and to study the
structural characteristics of single nucleosomes and their complexes with other macromolecules. Using
the example of a chromatosome, we demonstrate the fundamental possibility to obtain the geometry of
the linker DNA, which is important for the understanding the chromatin organization.
Acknowledgement
We thank M.P. Kirpichnikov, V.M. Studitskii, A.V. Feofanov, and the members of their
laboratories for providing the experimental data
Development of nucleosome visualization algorithms was supported by Russian Science
Foundation (grant No. 14-24-00031). A.S. was supported by the US–Russia Collaboration in the
Biomedical Sciences National Institutes of Health visiting fellows' program.
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IV INTERNATIONAL SCIENTIFIC CONFERENCE OF YOUNG RESEARCHERS
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Qafqaz University 29-30 April 2016, Baku, Azerbaijan
Another application of the WRF-Chem model is to understand high wintertime ozone pollution
events over the Uinta Basin, Utah. The basin is densely populated by thousands of oil and natural gas
wells. Our air quality simulations were able to reproduce the observed multi-day buildup of
atmospheric pollutants and accompanying rapid photochemical ozone formation in the Uinta Basin.
The model results demonstrate that very high emissions of volatile organic compounds associated with
oil and natural gas production, storage and processing contribute significantly to high ozone formation
over the in the Uinta Basin. Shallow boundary layers and snow cover are also key factors driving the
high ozone events in winter.
The state of the art WRF-Chem air quality model presented here may help to address the
emerging science and policy related questions related to air pollution over urban and industrial regions
across the globe.
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