RESUMO
The Mycobacterium tuberculosis genome possesses homologues of the ruvC and yqgF genes that encode putative Holliday junction (HJ) resolvases. However, their gene expression profiles and enzymatic properties have not been experimentally defined. Here we report that expression of ruvC and yqgF is induced in response to DNA damage. Protein-DNA interaction assays with purified M. tuberculosis RuvC (MtRuvC) and YqgF (MtRuvX) revealed that both associate preferentially with HJ DNA, albeit with differing affinities. Although both MtRuvC and MtRuvX cleaved HJ DNA in vitro, the latter displayed robust HJ resolution activity by symmetrically related, paired incisions. MtRuvX showed a higher binding affinity for the HJ structure over other branched recombination and replication intermediates. An MtRuvX(D28N) mutation, eliminating one of the highly conserved catalytic residues in this class of endonucleases, dramatically reduced its ability to cleave HJ DNA. Furthermore, a unique cysteine (C38) fulfils a crucial role in HJ cleavage, consistent with disulfide-bond mediated dimerization being essential for MtRuvX activity. In contrast, E. coli YqgF is monomeric and exhibits no branched DNA binding or cleavage activity. These results fit with a functional modification of YqgF in M. tuberculosis so that it can act as a dimeric HJ resolvase analogous to that of RuvC.
Assuntos
DNA Cruciforme/metabolismo , Proteínas de Ligação a DNA/metabolismo , Resolvases de Junção Holliday/metabolismo , Mycobacterium tuberculosis/enzimologia , Mycobacterium tuberculosis/genética , Cisteína , Dano ao DNA , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/isolamento & purificação , Escherichia coli/enzimologia , Escherichia coli/genética , Genoma Bacteriano , Resolvases de Junção Holliday/genética , Mycobacterium tuberculosis/efeitos da radiação , Multimerização Proteica , Análise de Sequência de DNA , Especificidade por Substrato , Raios UltravioletaRESUMO
The advent of biologic therapies has brought in significant improvement in the outcome of patients suffering from chronic inflammatory arthritis. High costs and unavailability have however, limited their utility in some parts of the world. These limitations have been overcome to a good extent by the introduction of biosimilar versions of original products, which are gaining momentum, of late. Adalimumab (Humira®), a TNF-α inhibitor has been successfully used in patients with inflammatory arthritis for more than a decade now. ZRC3197 (Adalimumab Biosimilar) was developed in India and approved for use since 2014. Ongoing evaluation of safety in real-world setting outside the context of controlled clinical trials is pivotal in ensuring long-term safety of such biologic therapies. We share the real-life safety profile of biosimilar Adalimumab in patients with chronic inflammatory arthritis and other autoimmune conditions from a tertiary care centre in south India.
Assuntos
Adalimumab/efeitos adversos , Antirreumáticos/efeitos adversos , Medicamentos Biossimilares/efeitos adversos , Doenças Reumáticas/tratamento farmacológico , Adalimumab/uso terapêutico , Antirreumáticos/uso terapêutico , Medicamentos Biossimilares/uso terapêutico , Feminino , Humanos , Índia , MasculinoRESUMO
We report the molecular docking analysis of four analogues of metformin [1-Carbamimidoyl-1,2-dimethylguanidine hydrochloride, Metformin hydrochloride, N1,N1-Dimethyl-N5-methylbiguanide hydrochloride, and N1,N1,N5,N5-Tetrakis (methyl-biguanide hydrochloride] with GSK3.