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41.
Banerjee S Mirsamadi N Anantharaman L Sivaram MV Gupta RB Choudhury D Roy RP 《The protein journal》2007,26(7):445-455
The identity of intermolecular contact residues in sickle hemoglobin (HbS) fiber is largely known. However, our knowledge
about combinatorial effects of two or more contact sites or the mechanistic basis of such effects is rather limited. Lys16,
His20, and Glu23 of the α-chain occur in intra-double strand axial contacts in the sickle hemoglobin (HbS) fiber. Here we
have constructed two novel double mutants, HbS (K16Q/E23Q) and (H20Q/E23Q), with a view to delineate cumulative impact of
interactions emanating from the above contact sites. Far-UV and visible region CD spectra of the double mutants were similar
to the native HbS indicating the presence of native-like secondary and tertiary structure in the mutants. The quaternary structures
in both the mutants were also preserved as judged by the derivative UV spectra of liganded (oxy) and unliganded (deoxy) forms
of the double mutants. However, the double mutants displayed interesting polymerization behavior. The polymerization behaviour
of the double mutants was found to be non-additive of the individual single mutants. While HbS (H20Q/E23Q) showed inhibitory
effect similar to that of HbS (E23Q), the intrinsic inhibitory propensity of the associated single mutants was totally quelled
in HbS (K16Q/E23Q) double mutant. Molecular dynamics (MD) simulations studies of the isolated α-chains as well as a module
of the fiber containing the double and associated single mutants suggested that these contact sites at the axial interface
of the fiber impact HbS polymerization through a coupled interaction network. The overall results demonstrate a subtle role
of dynamics and electrostatics in the polymer formation and provide insights about interaction-linkage in HbS fiber assembly. 相似文献
42.
Arup Kr. Malakar Debashree Choudhury Binata Halder Prosenjit Paul Arif Uddin Supriyo Chakraborty 《Journal of cellular physiology》2019,234(10):16812-16823
Coronary artery disease (CAD) is one of the major cardiovascular diseases affecting the global human population. This disease has been proved to be the major cause of death in both the developed and developing countries. Lifestyle, environmental factors, and genetic factors pose as risk factors for the development of cardiovascular disease. The prevalence of risk factors among healthy individuals elucidates the probable occurrence of CAD in near future. Genome-wide association studies have suggested the association of chromosome 9p21.3 in the premature onset of CAD. The risk factors of CAD include diabetes mellitus, hypertension, smoking, hyperlipidemia, obesity, homocystinuria, and psychosocial stress. The eradication and management of CAD has been established through extensive studies and trials. Antiplatelet agents, nitrates, β-blockers, calcium antagonists, and ranolazine are some of the few therapeutic agents used for the relief of symptomatic angina associated with CAD. 相似文献
43.
Giacomo Potente tienne Lveill-Bourret Narjes Yousefi Rimjhim Roy Choudhury Barbara Keller Seydina Issa Diop Daniël Duijsings Walter Pirovano Michael Lenhard Pter Szvnyi Elena Conti 《Molecular biology and evolution》2022,39(2)
Supergenes are nonrecombining genomic regions ensuring the coinheritance of multiple, coadapted genes. Despite the importance of supergenes in adaptation, little is known on how they originate. A classic example of supergene is the S locus controlling heterostyly, a floral heteromorphism occurring in 28 angiosperm families. In Primula, heterostyly is characterized by the cooccurrence of two complementary, self-incompatible floral morphs and is controlled by five genes clustered in the hemizygous, ca. 300-kb S locus. Here, we present the first chromosome-scale genome assembly of any heterostylous species, that of Primula veris (cowslip). By leveraging the high contiguity of the P. veris assembly and comparative genomic analyses, we demonstrated that the S-locus evolved via multiple, asynchronous gene duplications and independent gene translocations. Furthermore, we discovered a new whole-genome duplication in Ericales that is specific to the Primula lineage. We also propose a mechanism for the origin of S-locus hemizygosity via nonhomologous recombination involving the newly discovered two pairs of CFB genes flanking the S locus. Finally, we detected only weak signatures of degeneration in the S locus, as predicted for hemizygous supergenes. The present study provides a useful resource for future research addressing key questions on the evolution of supergenes in general and the S locus in particular: How do supergenes arise? What is the role of genome architecture in the evolution of complex adaptations? Is the molecular architecture of heterostyly supergenes across angiosperms similar to that of Primula? 相似文献
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46.
Sen P Mukherjee S Bhaumik G Das P Ganguly S Choudhury N Raha S 《Mutation research》2003,529(1-2):87-94
Exposure of Chinese hamster V79 fibroblasts to mild and repetitive H2O2 doses in culture for 15 weeks produced no change in lipid peroxidation status, GSH/GSSG ratio and glutathione peroxidase activity of these cells (VST cells). In contrast, in VST cells catalase levels underwent a prominent increase which could be significantly inhibited and brought down to control levels after treatment with the catalase inhibitor 3-aminotriazole (3-AT). When control (VC) cells were exposed to UV radiation (UVC 5 J/m2) or H2O2 (7.5mM, 15 min), intracellular reactive oxygen species (ROS) levels rose prominently with significant activation of caspase-3. Marked nuclear fragmentation and lower cell viability were also noted in these cells. In contrast, VST cells demonstrated a significantly lower ROS level, an absence of nuclear fragmentation and an unchanged caspase-3 activity after exposure to UVC or H2O2. Cell viability was also significantly better preserved in VST cells than VC cells after UV or H2O2 exposures. Following 3-AT treatment of VST cells, UVC radiation or H2O2 brought about significantly higher elevations in intracellular ROS, increases in caspase-3 activity, significantly lowered cell viability and marked nuclear fragmentation, indicating the involvement of high catalase levels in the cytoprotective effects of repetitive stress. Therefore, upregulation of the antioxidant defense after repetitive oxidative stress imparted a superior ability to cope with subsequent acute stress and escape apoptotic death and loss of viability. 相似文献
47.
Dasgupta J Sen U Choudhury D Datta P Chakrabarti A Chakrabarty SB Chakrabarty A Dattagupta JK 《Biochemical and biophysical research communications》2003,303(2):619-623
Hemoglobin A(2) (alpha(2)delta(2)), a minor (2-3%) component of circulating red blood cells, acts as an anti-sickling agent and its elevated concentration in beta-thalassemia is a useful clinical diagnostic. In beta-thalassemia major, where there is a failure of beta-chain production, HbA(2) acts as the predominant oxygen delivery mechanism. Hemoglobin E, is another common abnormal hemoglobin, caused by splice site mutation in exon 1 of beta globin gene, when combines with beta-thalassemia, causes severe microcytic anemia. The purification, crystallization, and preliminary structural studies of HbA(2) and HbE are reported here. HbA(2) and HbE are purified by cation exchange column chromatography in presence of KCN from the blood samples of individuals suffering from beta-thalassemia minor and E beta-thalassemia. X-ray diffraction data of HbA(2) and HbE were collected upto 2.1 and 1.73 A, respectively. HbA(2) crystallized in space group P2(1) with unit cell parameters a=54.33 A, b=83.73 A, c=62.87 A, and beta=99.80 degrees whereas HbE crystallized in space group P2(1)2(1)2(1) with unit cell parameters a=60.89 A, b=95.81 A, and c=99.08 A. Asymmetric unit in each case contains one Hb tetramer in R(2) state. 相似文献
48.
Abu AA Joseph D Suprasanna P Choudhury RK Saxena A Bapat VA 《Biological trace element research》2002,85(3):255-267
Drought-tolerant and drought-susceptible genotypes of sorghum (Sorghum bicolor L. Monech) were analyzed by the energy-dispersive X-ray fluorescence (EDXRF) technique to study the correlation of trace
elements with drought-tolerance capacities. Samples prepared from mature seeds, young seedlings, and old plants were analyzed
using a 109Cd radioisotope source and a Si(Li) semiconductor detector of resolution 170 eV for 5.9-keV MnK{ie255-1} X-rays. Elements such as K, Fe, Cu, Zn, Rb and Sr and Y were found to be present in varying concentrations in different
samples. The trace element profile studied in the seeds of 11 genotypes and in seedlings (young and old) of 4 sorghum genotypes
showed considerable variation. The genotype Arfa Gadamak (AG) showed a distinct presence of a high level of Zn in its young
seedling. It was observed that in most of the genotypes (seeds), K and Fe concentrations were more in the tolerant genotype
as compared to the susceptible type. The concentration of Fe decreased with maturity in the tolerant group and it increased
with maturity in the susceptible group. 相似文献
49.
Ghosh Choudhury G Ricono JM 《Biochemical and biophysical research communications》2000,273(3):1069-1077
50.
BACKGROUND: Localized tenosynovial giant cell tumor of tendon sheath (TGCT-L) is a benign, slowly growing lesion with a peak incidence in the third to fifth decade of life. It is thought to arise from the synovium of tendon sheaths, frequently affecting interphalangeal joints of the hands, feet, ankles and knees. Although the histopathologic appearances are well established, only a few reports describe the cytomorphology of this lesion. CASE: A 37-year-old female presented with a slowly growing, nontender mass located near the left ankle joint. The cytologic features of localized tenosynovial giant cell tumor of tendon sheath (TGCT-L) include abundant mononuclear histiocytic cells occurring singly and in three-dimensional tissue fragments, hemosiderin within histiocytes and a few multinucleated giant cells. Subsequently, the histopathologic examination of the surgical specimen was proven to be TGCT-L. CONCLUSION: Fine needle aspiration cytology can be used as a diagnostic tool for early and accurate detection of TGCT-L since the cytologic features combined with clinical details are sufficiently distinctive. 相似文献