Oral Biol Res.  2021 Dec;45(4):182-186. 10.21851/obr.45.04.202112.182.

Characterization of Congo red binding in Streptococcus gordonii

• Kim EJ
• Lee SY

• KMID: 2524712
• DOI: http://doi.org/10.21851/obr.45.04.202112.182

Abstract

Iron is essential for bacterial growth. The ability to use heme compounds to derive iron in pathogenic bacteria has been reported. In some pathogenic bacteria, studies indicated that hemin binding is related to their Congo red binding abilities. In this study, we investigated the Congo red binding of Streptococcus gordonii, an oral streptococcus, to characterize the association between Congo red and hemin binding. Bacteria and Congo red were mixed and incubated. After centrifugation, the optical density of the supernatant was measured, and the amount of Congo red bound to bacteria was determined using a Congo red standard curve. Adhesion competition analysis between hemin and Congo red in bacteria was also conducted by the pre-binding of S. gordonii to hemin and then analyzing Congo red binding. The ability of S. gordonii to bind Congo red was increased depending on added bacteria and Congo red quantities. Inhibition of the Congo red binding ability to S. gordonii was dependent on pre-bound hemin levels. These data suggested that S. gordonii bound Congo red and may contain Congo red binding sites. Competitive analyses also indicated that Congo red and hemin binding in S. gordonii may be related.

Keyword

Congo red; Hemin; Ligand binding; Streptococcus gordonii