Udayaditya Sen

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The APOBEC family members are involved in diverse biological functions. APOBEC3G restricts the replication of human immunodeficiency virus (HIV), hepatitis B virus and retroelements by cytidine deamination on single-stranded DNA or by RNA binding. Here we report the high-resolution crystal structure of the carboxy-terminal deaminase domain of APOBEC3G(More)
As a part of studies on the structural characterization of the components of the sporulation phosphorelay in Bacillus subtilis, the crystal structure of the manganese derivative of an intermediate signal transducer, Spo0F, has been elucidated at 2.25 A resolution. The calcium complex and the apo structures have been analyzed previously. In apo Spo0F, the(More)
The crystal structure of a Kunitz-type double-headed alpha--chymotrypsin inhibitor from winged bean seeds has been refined at 2.13 A resolution using data collected from cryo-cooled (90 K) crystals which belong to the hexagonal space group P6(1)22 with unit-cell parameters a = b = 60.84, c = 207.91 A. The volume of the unit cell is reduced by 5.3% on(More)
Thc crystal structure of an alpha-chymotrypsin inhibitor (P6(1)22; a = 61.4, c = 210.9 A) isolated from winged bean (Psophocarpus. tetragonolobus) seeds has been determined at 2.95 A resolution by the molecular-replacement method using the 2.6 A coordinates of Erythrina trypsin inhibitor (ETI) as the starting model (57% sequence homology). This protease(More)
The crystal structure of a double-headed alpha-chymotrypsin inhibitor, WCI, from winged bean seeds has now been refined at 2.3 A resolution to an R-factor of 18.7% for 9,897 reflections. The crystals belong to the hexagonal space group P6(1)22 with cell parameters a = b = 61.8 A and c = 212.8 A. The final model has a good stereochemistry and a root mean(More)
Hemoglobin A(2) (alpha(2)delta(2)) is an important hemoglobin variant which is a minor component (2-3%) in the circulating red blood cells, and its elevated concentration in beta-thalassemia is a useful clinical diagnostic. In beta-thalassemia major, where there is beta-chain production failure, HbA(2) acts as the predominant oxygen deliverer. HbA(2) has(More)
Change in specificity, caused by the mutations at P1 site, of the serine protease inhibitors of different families is reported in the literature, but Kunitz (STI) family inhibitors are almost unexplored in this regard. In this paper, we present the crystal structure of a P1 variant of winged bean chymotrypsin inhibitor (WCI) belonging to Kunitz (STI)(More)
The lymphoid tyrosine phosphatase (LYP), encoded by the PTPN22 gene, recently emerged as an important risk factor and drug target for human autoimmunity. Here we solved the structure of the catalytic domain of LYP, which revealed noticeable differences with previously published structures. The active center with a semi-closed conformation binds a phosphate(More)
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,(More)
The conserved bacterial transcription terminator, Rho, is a potent target for bactericidal agents. Psu, a bacteriophage P4 capsid protein, is capable of inducing anti-termination to the Rho-dependent transcription termination. Knowledge of structural and mechanistic basis of this anti-termination is required to design peptide-inhibitor(s) of Rho from Psu.(More)