Helicobacter pylori periplasmic receptor CeuE (HP1561) modulates its nickel affinity via organic metallophores. Issue 4 (7th January 2014)

• Record Type: Journal Article
• Authors: Shaik, Md Munan; Cendron, Laura; Salamina, Marco; Ruzzene, Maria; Zanotti, Giuseppe
• Is Part Of: Molecular microbiology. Volume 91:Issue 4(2014)
• Page Start: 724
• Page End: 735
• Publication Date: 2014-01-07
• Subjects: Molecular microbiology -- Periodicals; 572.829
• DOI: 10.1111/mmi.12487
• Languages: English
• ISSNs: 0950-382X

Abstract

<abstract abstract-type="main"> <title>Summary</title> <p>In Gram‐negative bacteria, nickel uptake is guaranteed by multiple and complex systems that operate at the membrane and periplasmic level. <italic>H</italic><italic>elicobacter pylori</italic> employs other yet uncharacterized systems to import the nickel required for the maturation of key enzymes, such as urease and hydrogenase. <italic>H</italic><italic>. pylori </italic>CeuE protein (HP1561), previously annotated as the periplasmic component of an ATP‐binding cassette (ABC)‐type transporter apparatus responsible of haem/siderophores or other Fe(III)‐complexes uptake, has been recently proposed to be on the contrary involved in nickel/cobalt acquisition. In this work, the crystal structure of <italic>H</italic><italic>. pylori </italic>CeuE has been determined at 1.65 Å resolution using the single anomalous dispersion (SAD) method. It comprises two structurally similar globular domains, each consisting of a central five‐stranded β‐sheet surrounded by α‐helices, an arrangement commonly classified as a Rossmann‐like fold. Structurally, <italic>H</italic><italic>. pylori </italic>CeuE belongs to the class III periplasmic substrate‐binding protein. Both crystallographic data and fluorescence binding assays allow to exclude a role of the protein in the transport of Vitamin B12, enterobactin, haem and isolated Ni<sup>2+</sup> ions. On the contrary, the crystal structure and plasmon resonance studies about CeuE/Ni‐(<sc>l</sc>‐His)<sub>2</sub> complex indicate that in <italic>H</italic><italic>. pylori</italic> nickel transport is supported by CeuE protein and requires the presence of a natural nickelophore, analogously to what has been recently demonstrated for NikA from <italic>E</italic><italic>scherichia coli</italic>.</p> </abstract>