Structure of a complex of human lactoferrin N-lobe with pneumococcal surface protein a provides insight into microbial defense mechanism.

ABSTRACT: Human lactoferrin, a component of the innate immune system, kills a wide variety of microorganisms including the Gram positive bacteria Streptococcus pneumoniae. Pneumococcal surface protein A (PspA) efficiently inhibits this bactericidal action. The crystal structure of a complex of the lactoferrin-binding domain of PspA with the N-lobe of human lactoferrin reveals direct and specific interactions between the negatively charged surface of PspA helices and the highly cationic lactoferricin moiety of lactoferrin. Binding of PspA blocks surface accessibility of this bactericidal peptide preventing it from penetrating the bacterial membrane. Results of site-directed mutagenesis, in vitro protein binding assays and isothermal titration calorimetry measurements corroborate that the specific ele

SUBMITTER: Senkovich O 

PROVIDER: S-EPMC5356469 | biostudies-literature | 2007 Jul

REPOSITORIES: biostudies-literature