An ATP-binding cassette-type cysteine transporter in Campylobacter jejuni inferred from the structure of an extracytoplasmic solute receptor protein.

Autor(es): Müller Axel,Thomas Gavin H,Horler Richard,Brannigan James A,Blagova Elena,Levdikov Vladimir M,Fogg Mark J,Wilson Keith S,Wilkinson Anthony J

Resumo: Campylobacter jejuni is a Gram-negative food-borne pathogen associated with gastroenteritis in humans as well as cases of the autoimmune disease Guillain-Barré syndrome. C. jejuni is asaccharolytic because it lacks an active glycolytic pathway for the use of sugars as a carbon source. This suggests an increased reliance on amino acids as nutrients and indeed the genome sequence of this organism indicates the presence of a number of amino acid uptake systems. Cj0982, also known as CjaA, is a putative extracytoplasmic solute receptor for one such uptake system as well as a major surface antigen and vaccine candidate. The crystal structure of Cj0982 reveals a two-domain protein with density in the enclosed cavity between the domains that clearly defines the presence of a bound cysteine ligand. Fluorescence titration experiments were used to demonstrate that Cj0982 binds cysteine tightly and specifically with a K(d) of approximately 10(-7) M consistent with a role as a receptor for a high-affinity transporter. These data imply that Cj0982 is the binding protein component of an ABC-type cysteine transporter system and that cysteine uptake is important in the physiology of C. jejuni.

Imprenta: Molecular Microbiology, v. 57, n. 1, p. 143-155, 2005

Identificador do objeto digital: 10.1111/j.1365-2958.2005.04691.x

Descritores: Guillain-Barre Syndrome - Biosynthesis ; Guillain-Barre Syndrome - Cell ; Guillain-Barre Syndrome - Genome ; Guillain-Barre Syndrome - Molecular Structure ; Guillain-Barre Syndrome - Pathogenesis ; Guillain-Barre Syndrome - Proteins ; Guillain-Barre Syndrome - Vaccine

Data de publicação: 2005