A novel mode of ferric ion coordination by the periplasmic ferric ion-binding subunit FbpA of an ABC-type iron transporter from Thermus thermophilus HB8

作者：Wang Shipeng; Ogata Misaki; Horita Shoichiro; Ohtsuka Jun; Nagata Koji; Tanokura Masaru^*

来源：Acta Crystallographica Section D-Biological Crystallography, 2014, 70: 196-202.

DOI：10.1107/S1399004713026333

Crystal structures of FbpA, the periplasmic ferric ion-binding protein of an iron-uptake ABC transporter, from Thermus thermophilus HB8 (TtFbpA) have been solved in apo and ferric ion-bound forms at 1.8 and 1.7 angstrom resolution, respectively. The latter crystal structure shows that the bound ferric ion forms a novel six-coordinated complex with three tyrosine side chains, two bicarbonates and a water molecule in the metal-binding site. The results of gel-filtration chromatography and dynamic light scattering show that TtFbpA exists as a monomer in solution regardless of ferric ion binding and that TtFbpA adopts a more compact conformation in the ferric ion-bound state than in the apo state in solution.

• 出版日期2014-1