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A homology model of the enzyme was developed to study and examine the structural and functional significance of the interaction between Dda helicase from bacteriophage T4 and DNA and effect of such interaction on translocation and unwinding of DNA. The performance of the model was confirmed by using methods for mapping protein domains and for examining protein surfaces that interact with DNA.

A 3-year-old spayed female rabbit developed chronic coughing and gagging after removal of a nasogastric tube placed for medical management of gastrointestinal stasis. Radiographs revealed a tubular structure that appeared to be located in the proximal trachea. The foreign body was removed using rigid tracheoscopy and determined to be the distal 15 cm of the nasogastric tube. The rabbit was discharged the same day and the owner reported that its clinical signs completely resolved after removal of the foreign body. [ABSTRACT FROM AUTHOR]

Aberrations in epigenetic processes, such as histone methylation, can cause cancer. Retinoblastoma binding protein 2 (RBP2; also called JARID1A or KDM5A) can demethylate tri- and dimethylated lysine 4 in histone H3, which are epigenetic marks for transcription- ally active chromatin, whereas the multiple endocrine neoplasia type 1 (MEN1) tumor suppressor promotes H3K4 methylation. Previous studies suggested that inhibition of RBP2 contributed to tumor suppression by the retinoblastoma protein (pRB). Here, we show that genetic ablation of Rbp2 decreases tumor formation and prolongs survival in Rb1+/- mice and Menl-defective mice. These studies link RBP2 histone demethylase activity to tumorigenesis and nominate RBP2 as a potential target for cancer therapy. [ABSTRACT FROM AUTHOR]

In eukaryotes, DNA is wrapped around proteins called histones and is condensed into chromatin. Post-translational modification of histones can result in changes in gene expression. One of the most well-studied histone modifications is the methylation of lysine 4 on histone H3 (H3K4). This residue can be mono-, di- or tri-methylated and these varying methylation states have been associated with different levels of gene expression. Understanding exactly what the purpose of these methylation states is, in terms of gene expression, has been a topic of much research in recent years. Enzymes that can add (methyltransferases) and remove (demethylases) these modifications are of particular interest. The first demethylase discovered, LSD1, is the most well-classified and has been implicated in contributing to human cancers and to DNA damage response pathways. Currently, there are limited methods for accurately studying the activity of demethylases in vitro or in vivo. In this work, we present MassSQUIRM (mass spectrometric quantitation using isotopic reductive methylation), a quantitative method for studying the activity of demethylases capable of removing mono- and di-methyl marks from lysine residues. We focus specifically on LSD1 due to its potential as a prime therapeutic target for human disease. This quantitative approach will enable better characterization of the activity of LSD1 and other chromatin modifying enzymes in vitro, in vivo or in response to inhibitors.