97 research outputs found

    Crystallographic Evidence of Drastic Conformational Changes in the Active Site of a Flavin-Dependent

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    The soil actinomycete Kutzneria sp. 744 produces a class of highly decorated hexadepsipeptides, which represent a new chemical scaffold that has both antimicrobial and antifungal properties. These natural products, known as kutznerides, are created via nonribosomal peptide synthesis using various derivatized amino acids. The piperazic acid moiety contained in the kutzneride scaffold, which is vital for its antibiotic activity, has been shown to derive from the hydroxylated product of l-ornithine, l-N5-hydroxyornithine. The production of this hydroxylated species is catalyzed by the action of an FAD- and NAD(P)H-dependent N-hydroxylase known as KtzI. We have been able to structurally characterize KtzI in several states along its catalytic trajectory, and by pairing these snapshots with the biochemical and structural data already available for this enzyme class, we propose a structurally based reaction mechanism that includes novel conformational changes of both the protein backbone and the flavin cofactor. Further, we were able to recapitulate these conformational changes in the protein crystal, displaying their chemical competence. Our series of structures, with corroborating biochemical and spectroscopic data collected by us and others, affords mechanistic insight into this relatively new class of flavin-dependent hydroxylases and adds another layer to the complexity of flavoenzymes.National Center for Research Resources (U.S.) (P41RR012408)National Institute of General Medical Sciences (U.S.) (P41GM103473

    Fungal volatile organic compounds: emphasis on their plant growth-promoting

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    Fungal volatile organic compounds (VOCs) commonly formed bioactive interface between plants and countless of microorganisms on the above- and below-ground plant-fungus interactions. Fungal-plant interactions symbolize intriguingly biochemical complex and challenging scenarios that are discovered by metabolomic approaches. Remarkably secondary metabolites (SMs) played a significant role in the virulence and existence with plant-fungal pathogen interaction; only 25% of the fungal gene clusters have been functionally identified, even though these numbers are too low as compared with plant secondary metabolites. The current insights on fungal VOCs are conducted under lab environments and to apply small numbers of microbes; its molecules have significant effects on growth, development, and defense system of plants. Many fungal VOCs supported dynamic processes, leading to countless interactions between plants, antagonists, and mutualistic symbionts. The fundamental role of fungal VOCs at field level is required for better understanding, so more studies will offer further constructive scientific evidences that can show the cost-effectiveness of ecofriendly and ecologically produced fungal VOCs for crop welfare

    A Five-Factor Theory Perspective

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    Abstract. Five-Factor Theory (FFT) is a conceptualization of the personality system that identifies traits as abstract Basic Tendencies rooted in biology. In this chapter, FFT is examined in relation to recent findings in cross-cultural psychology reported in this volume. FFT correctly predicts the universality of personality structure, maturation, and gender differentiation. FFT suggests that differences in the mean levels of traits across cultures may be due to differences in the distribution of trait-related alleles, and that cultural dif-ferences may be the effect, rather than the cause, of trait level differences. Reports of substantial cohort and acculturation effects pose challenges to FFT and provide special opportunities for future research

    Color-Orientation Indexing

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    Observing the development of content based image retrieval systems hindered by the lack of efficient image representations, color histogram based indexing techniques have been used quite successfully. Though their performance strongly depends on illumination conditions being controlled, there has been only small effort to make them invariant to illumination. By introducing color-orientation histograms we present an integrated representation for color and local orientation, achieving robustness to several illumination conditions for free. Our method involves steerable filter techniques and Lab-color space conversion

    Selective Control of Downy Brome in Alfalfa

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    Technology based industrial product-services supporting robustness in manufacturing systems

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    Uncertainty affecting manufacturing systems or networks asks for approaches able to smoothing the negative effects of disturbances coming both from the plant and supply chain levels. Thus, the objective of this paper is to investigate the capability of product-services business models of increasing companies robustness, towards internal and external disturbances in highly dynamic environments. This work is part of the EU project RobustPlaNet, which investigates this topic in the context of three industrial areas, i.e. automotive, aerospace and industrial automation. The analysis is carried out on a case study in the field of equipment reliability in order to demonstrate the formalization of business models for industrial product-services that support systems’ robustness

    Involvement of common intermediate 3-hydroxy-L-kynurenine in chromophore biosynthesis of quinomycin family antibiotics

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    Quinomycin antibiotics, represented by echinomycin, are an important class of antitumor antibiotics. We have recently succeeded in identification of biosynthetic gene clusters of echinomycin and SW-163D, and have achieved heterologous production of echinomycin in Escherichia coil. In addition, we have engineered echinomycin nonribosomal peptide synthetase (NRPS) to generate echinomycin derivatives. However, the biosynthetic pathways of intercalative chromophores quinoxaline-2-carboxylic acid (QXC) and 3-hydroxyquinaldic acid (HQA), which are important for biological activity, were not fully elucidated. Here, we report experiments involving incorporation of a putative advanced precursor, (2S, 3R)-[6'-2H]-3-hydroxy-L-kynurenine, and functional analysis of the enzymes Swb1 and Swb2 responsible for late-stage biosynthesis of HQA. Based on these experimental results, we propose biosynthetic pathways for both QXC and HQA via the common intermediate 3-hydroxy-L-kynurenine
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