RNase P is the enzyme that removes 5' extensions from tRNA precursors. With its diversity of enzyme forms-either protein- or RNA-based, ranging from single polypeptides to multi-subunit ribonucleoproteins-the RNase P enzyme family represents a unique model system to compare the evolution of enzymatic mechanisms. Here we present a comprehensive study of substrate recognition and cleavage-site se...

The widely accepted model for the processing of tRNAs in Escherichia coli involves essential initial cleavages by RNase E within polycistronic transcripts to generate pre-tRNAs that subsequently become substrates for RNase P. However, recently we identified two polycistronic tRNA transcripts whose endonucleolytic processing was solely dependent on RNase P. Here we show that the processing of th...

We investigate the analyticity property of the partially resummed series expansion(PRSE) of the partition function for the eight-vertex model. Developing a graphical technique, we have obtained a first few terms of the PRSE and found that these terms have a pole only at one point in the complex plane of the coupling constant. This result supports the conjecture proposed by Guttmann and Enting c...

in recent years, researchers have become interested in examining the effect of pettlep imagery on motor performance and how pettlep imagery can improve the performance. the aim of this study was to compare the effect of pettlep imagery and balance practice on dynamic balance in the elderly. participants were 42 male elderly in arak city. they were divided into 4 groups based on the scores of dy...

Introduction: According to the American Society of Radiation Oncology, all patients receive radiation therapy during their illness, where radiation is delivered by the medical linear accelerator (Linac). The aim of this study was to evaluate the quality assurance (QA) of the Linac in analyzing the used dose profile in the treatment of cancer tumors. Materi...

Background Access to appropriate images of fetal brain can greatly assist to diagnose of probable abnormalities. The aim of this study was to compare the suitability of T2-True Fast Imaging with Steady State Free Precession (T2-TRUFI), and T2-Half-Fourier Acquisition Single-Shot Turbo Spin-Echo (T2- HASTE( magnetic resonance imaging (MRI) to extract the fetal brain using the level set algorithm...

Background: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders, affecting 5-10% of reproductive aged women. High levels of androgen hormone can be accounted as the most important symptoms in PCOS. Androgen is the precursor of steroid biosynthesis in ovary. The transport of cholesterol to the inner mitochondrial membrane through StAR protein is also necessary for andr...

It has been suggested that Alba, a well-established chromatin protein in Archaea, is also a subunit of the archaeal RNase P holoenzyme, based on the observation that the homolog of this protein in humans has been shown to be associated with RNase P activity. Using the same biochemical methods we used previously to show that four other proteins homologous to eukaryotic RNase P proteins are bona ...