Reverse gyrases are topoisomerases that introduce positive supercoils into DNA in an ATP-dependent reaction. They consist of a helicase domain and a topoisomerase domain that closely cooperate in catalysis. The mechanism of the functional cooperation of these domains has remained elusive. Recent studies have shown that the helicase domain is a nucleotide-regulated conformational switch that alt...

Using the single-strand conformational polymorphism technique, we have screened 66 malignant ovarian tumors for p53 mutation in exons 5 to 8. Thirty-four of the tumors demonstrated a single-strand conformational polymorphism band shift in this region of the gene, including 6 in exon 5, 7 in exon 6, 12 in exon 7, and 10 in exon 8 (one of the tumors showed a shift for exons 7 and 8). All of the s...

A two-stranded alpha-helical coiled coil was prepared having a Cys 4 metal-binding site within its hydrophobic interior. The addition of Cd2+ results in the incorporation of 2 equiv of metal ion, which is accompanied by a conformational change of the peptide, as observed by circular dichroism (CD) spectroscopy. Isothermal titration calorimetry (ITC) shows that the addition of Cd2+ is accompanie...

Small oligomers formed early along human islet amyloid polypeptide (hIAPP) aggregation is responsible for the cell death in Type II diabetes. The epigallocatechin gallate (EGCG), a green tea extract, was found to inhibit hIAPP fibrillation. However, the inhibition mechanism and the conformational distribution of the smallest hIAPP oligomer - dimer are mostly unknown. Herein, we performed extens...

Single-stranded DNA (ssDNA) is characterized by high conformational flexibility that allows these molecules to adopt a variety of conformations. Here we used native polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy to show that cytosine methylation at CpG sites affects the conformational flexibility of short ssDNA m...

Nucleic acid molecules can adopt a variety of structures and exhibit a large degree of conformational flexibility to fulfill their various functions in cells. Here we describe the use of Pulsed Electron-Electron Double Resonance (PELDOR or DEER) to investigate nucleic acid molecules where two cytosine analogs have been incorporated as spin probes. Because these new types of spin labels are rigi...

conclusions we concluded from the results that the frequency of emb-resistant m. tuberculosis cases in iran is lower than that of many other regions. the pcr-sscp technique can separate resistant isolates from sensitive isolates. the sequencing results of this study showed mutation in codons 309 and 299 of the embb gene. in none of the resistant isolates, mutation was observed in codon 306. fur...

Structural DNA nanotechnology, the assembly of rigid 3D structures of complex yet precise geometries, has recently been used to design dynamic, mechanically compliant nanostructures with tunable equilibrium conformations and conformational distributions. Here we use coarse-grained molecular dynamics simulations to provide insights into the conformational dynamics of a set of mechanically compli...

placental lactogen is a polypeptide hormone that is produced by the placenta, also known as chorionic somatomammotropin hormone. it has both growth hormone and prolactin activities on growth, lactation, and luteal steroid production. the objective of this study was to investigate the bovine placental lactogen (bpl) gene polymorphism of holstein cows in razavi khorasan province. blood samples we...

The aim was to detect the presence of polymorphisms at exons 1, 2, 3 and 4 of the Spi2 gene, and evaluate a possible association between them and recurrent airway obstruction (RAO) or inflammatory airway disease (IAD) in thoroughbred horses, through single-strand conformational-polymorphism (SSCP) screening. Although polymorphism was not detected in exons 1, 2 and 3, three alleles and six genot...