Characterization of the gene cluster involved in allantoate catabolism and its transcriptional regulation by the RpiR-type repressor HpxU in Klebsiella pneumoniae Authors Karla Guzmán Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Evangelina Campos Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Laura Aguilera Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Lorena Toloza Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Rosa Giménez Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Juan Aguilar Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Laura Baldoma Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Josefa Badia Department of Biochemistry and Molecular Biology, Institute of Biomedicine, Faculty of Pharmacy, University of Barcelona, Barcelona, Spain Keywords: Klebsiella pneumoniae, allantoate metabolism, allantoate amidohydrolase, purine catabolism, RpiR-type repressor Abstract Bacteria, fungi, and plants have metabolic pathways for the utilization of nitrogen present in purine bases. In Klebsiella pneumoniae, the genes responsible for the assimilation of purine ring nitrogen are distributed in three separated clusters. We characterized the gene cluster involved in the metabolism of allantoate (genes KPN_01761 to KPN_01771). The functional assignments of HpxK, as an allantoate amidohydrolase, and of HpxU, as a regulator involved in the control of allantoate metabolism, were assessed experimentally. Gene hpxU encodes a repressor of the RpiR family that mediates the regulation of this system by allantoate. In this study, the binding of HpxU to the hpxF promoter and to the hpxU-hpxW intergenic region containing the divergent promoter for these genes was evidenced by electrophoretic mobility shift assays. Allantoate released the HpxU repressor from its target operators whereas other purine intermediate metabolites, such as allantoin and oxamate, failed to induce complex dissociation. Sequence alignment of the four HpxU identifi ed operators identifi ed TGAA-N8-TTCA as the consensus motif recognized by the HpxU repressor. [Int Microbiol 2013; 16(3):XXX-XXX]Keywords: Klebsiella pneumoniae · allantoate metabolism · allantoate amidohydrolase · purine catabolism · RpiR-type repressor Downloads PDF Issue Vol. 16 No. 3 (2013) Section Research Articles License Submission of a manuscript to International Microbiology implies: that the work described has not been published before, including publication in the World Wide Web (except in the form of an Abstract or as part of a published lecture, review, or thesis); that it is not under consideration for publication elsewhere; that all the coauthors have agreed to its publication. The corresponding author signs for and accepts responsability for releasing this material and will act on behalf of any and all coauthors regarding the editorial review and publication process.If an article is accepted for publication in International Microbiology, the authors (or other copyright holder) must transfer to the journal the right–not exclusive–to reproduce and distribute the article including reprints, translations, photographic reproductions, microform, electronic form (offline, online) or any other reproductions of similar nature. Nevertheless, all article in International Microbiology will be available on the Internet to any reader at no cost. The journal allows users to freely download, copy, print, distribute, search, and link to the full text of any article, provided the authorship and source of the published article is cited. The copyright owner's consent does not include copying for new works, or resale. In these cases, the specific written permission of International Microbiology must first be obtained.Authors are requested to create a link to the published article on the journal's website. The link must be accompanied by the following text: "The original publication is available on LINK at <http://www.im.microbios.org>. Please use the appropiate URL for the article in LINK. Articles disseminated via LINK are indexed, abstracted, and referenced by many abstracting and information services, bibliographic networks, subscription agencies, library networks, and consortia.
