Crystal structures of bacterial Small Multidrug Resistance transporter EmrE in complex with structurally diverse substrates

Proteins from the bacterial small multidrug resistance (SMR) family are proton-coupled exporters of diverse antiseptics and antimicrobials, including polyaromatic cations and quaternary ammonium compounds. The transport mechanism of the Escherichia coli transporter, EmrE, has been studied extensively, but a lack of high-resolution structural information has impeded a structural description of its molecular mechanism. Here we apply a novel approach, multipurpose crystallization chaperones, to solve several structures of EmrE, including a 2.9 Å structure at low pH without substrate. We report five additional structures in complex with structurally diverse transported substrates, including quaternary phosphonium, quaternary ammonium, and planar polyaromatic compounds. These structures show that binding site tryptophan and glutamate residues adopt different rotamers to conform to disparate structures without requiring major rearrangements of the backbone structure. Structural and functional comparison to Gdx-Clo, an SMR protein that transports a much narrower spectrum of substrates, suggests that in EmrE, a relatively sparse hydrogen bond network among binding site residues permits increased sidechain flexibility.

The Exploration of mystical experiences among religious preachers

The current qualitative study aimed to explore the Mystical Experiences among religious preachers. A Purposive sampling technique was employed to select a sample of (n=10) religious preachers who had encountered at least one mystical experience. The transcendental phenomenological approach was used to capture the essence of the mystical experiences, through in-depth semi structured interview guide which was developed based on five domains namely exploration of mystic features, beliefs, impact on life, sharing of mystical experiences as well as the religious and cultural oriented explanations. Initially, a pilot study was conducted to assess the feasibility of the semi-structured in-depth interview guide and also to finalize the road map for the main study. The main study was conducted after incorporating changes in the pilot study. The modification of Stevick-Colaizzi-Keen’s model by Maustakas (1994) was employed for data analysis followed through a series of steps such as bracketing, horizonalization of data, grouping of significant statements to constitute themes (triggers, perceptual experience, symbolism and derived meanings, significant figures, reaction, and the cultural explanation of mystical experiences), textural description (‘what’ happened during a mystical experience) and a structural description (‘how’ this experienced occurred) with verbatim examples was developed. Both these descriptions were combined to write a composite description that reflected the ‘essence’ of the mystical experiences and highlighted the causes, characteristics, perceptual experiences, beliefs, and its impact. The findings highlighted the subjective nature of the mystical experiences and the need to develop an indigenous formal criterion for the identification of such experiences.

Plastics degradation by hydrolytic enzymes: the Plastics-Active Enzymes Database - PAZy

Petroleum based plastics are durable and accumulate in all ecological niches. Knowledge on enzymatic degradation is sparse. Today, less than 50 verified plastics-active enzymes are known. First examples of enzymes acting on the polymers polyethylene terephthalate (PET) and polyurethane (PUR) have been reported together with a detailed biochemical and structural description. Further, very few polyamide (PA) oligomer active enzymes are known. In this paper, the current known enzymes acting on the synthetic polymers PET and PUR are briefly summarized, their published activity data were collected and integrated into a comprehensive open access database. The Plastics-Active Enzymes Database (PAZy) represents an inventory of known and experimentally verified plastics-active enzymes. Almost 3000 homologues of PET-active enzymes were identified by profile hidden Markov models. Over 2000 homologues of PUR-active enzymes were identified by BLAST. Based on multiple sequence alignments, conservation analysis identified the most conserved amino acids, and sequence motifs for PET- and PUR-active enzymes were derived.

Structural description and tectonic development history of the mesozoic deposits in the Vilyui hemisyneclise

We present the interpretation of 2D seismic data in the Vilyui hemisyneclise located in the Republic of Sakha (Yakutia). The model identifies structural and tectonic features and tectonic development history of the Mesozoic deposits in the Vilyui hemisyneclise. Structure contour maps for the reflecting horizons of the Mesozoic are qualitatively the same. Traced faults attenuate at various stratigraphic levels. The structures of the hemisyneclise are known to be formed during the Cretaceous stage of development.

Detection and study of polarized pulsed photoluminescence of diamonds for mapping of natural diamond

The bulk mapping of natural diamond poses problems where it is required to characterize various defects and measure their optical properties in volume. The combination of photoluminescence spectroscopy methods and methods for detecting the state of polarization in the volume will expand the functionality for mapping natural and artificial diamonds. The implemented methods will be an effective tool for the structural description of diamond optical centers.

Keratin-Based Nanoparticles as Drug Delivery Carriers

Keratin is a structural protein of mammalian tissues and birds, representing the principal constituent of hair, nails, skin, wool, hooves, horns, beaks, and feathers, and playing an essential role in protecting the body from external harassment. Due to its intrinsic features such as biocompatibility, biodegradability, responsiveness to specific biological environment, and physical–chemical properties, keratin has been extensively explored in the production of nanocarriers of active principles for different biomedical applications. In the present review paper, we aimed to give a literature overview of keratin-based nanoparticles produced starting from human hair, wool, and chicken feathers. Along with the chemical and structural description of keratin nanoparticles, selected in vitro and in vivo biological data are also discussed to provide a more comprehensive framework of possible fields of application of this protein. Despite the considerable number of papers describing the production and use of keratin nanoparticles as carries of anticancer and antimicrobial drugs or as hemostatic and wound healing materials, still, efforts are needed to implement keratin nanoparticles towards their clinical application.

Structure, Engagement, and Evolution

This chapter provides a structural description of movie units, defends the notion that movies have evolved in the direction of fitting better our capacities and preferences, and summarizes evidence that the evolved changes have encouraged narrative engagement by viewers. Arguments against any true evolution of cinema concern reproduction, genes, random variation and selection, fashion, progression, speciation, and directionality, and these are discussed and all but the means of reproduction countered. The chapter then summarizes results of the previous chapters about how narrative engagement is attained through sustained attentional focus, understanding the narrative, emotional commitment, and a feeling of presence. It also warns the reader that increased engagement does not mean better movies. Engagement is driven by the narration; the quality of the movie is surely driven by the narrative.