Identification of a lactoferrin-binding protein in Prevotella nigrescens.

A 40-kDa lactoferrin-binding protein was identified in a strain of Prevotella nigrescens isolated from a patient with periodontitis. The protein was purified by affinity column chromatography using a Sepharose-lactoferrin column and detergent-solubilized membranes. The N-terminal sequence revealed no apparent similarities with any other sequenced bacterial protein. The native conformation of the 40-kDa protein was a condition to bind either iron-free or iron-saturated lactoferrin. A possible function of this Lf-binding protein could be related with an iron acquisition mechanism in P. nigrescens.