Lipoprotein FtsB in Streptococcus pyogenes binds ferrichrome in two steps with residues Tyr137 and Trp204 as critical ligands.

ABSTRACT: Lipoprotein FtsB is a component of the FtsABCD transporter that is responsible for ferrichrome binding and uptake in the Gram-positive pathogen Streptococcus pyogenes. In the present study, FtsB was cloned and purified from the bacteria and its Fch binding characteristics were investigated in detail by using various biophysical and biochemical methods. Based on the crystal structures of homogeneous proteins, FtsB was simulated to have bi-lobal structure forming a deep cleft with four residues in the cleft as potential ligands for Fch binding. With the assistance of site-directed mutagenesis, residue Trp204 was confirmed as a key ligand and Tyr137 was identified to be another essential residue for Fch binding. Kinetics experiments demonstrated that Fch binding in FtsB occurred in two steps,

SUBMITTER: Li H 

PROVIDER: S-EPMC3688767 | biostudies-literature | 2013

REPOSITORIES: biostudies-literature