Download MendeleyMolecular basis of hemoglobin binding and heme removal in Corynebacterium diphtheriae.
Mahoney, B.J., Lyman, L.R., Ford, J., Soule, J., Cheung, N.A., Goring, A.K., Ellis-Guardiola, K., Collazo, M.J., Cascio, D., Ton-That, H., Schmitt, M.P., Clubb, R.T.(2025) Proc Natl Acad Sci U S A 122: e2411833122-e2411833122
- PubMed: 39739808
- DOI: https://doi.org/10.1073/pnas.2411833122
- Primary Citation of Related Structures:
9BCH, 9BCJ - PubMed Abstract:
To successfully mount infections, nearly all bacterial pathogens must acquire iron, a key metal cofactor that primarily resides within human hemoglobin. Corynebacterium diphtheriae causes the life-threatening respiratory disease diphtheria and captures hemoglobin for iron scavenging using the surface-displayed receptor HbpA. Here, we show using X-ray crystallography, NMR, and in situ binding measurements that C. diphtheriae selectively captures iron-loaded hemoglobin by partially ensconcing the heme molecules of its α subunits. Quantitative growth and heme release measurements are compatible with C. diphtheriae acquiring heme passively released from hemoglobin's β subunits. We propose a model in which HbpA and heme-binding receptors collectively function on the C. diphtheriae surface to capture hemoglobin and its spontaneously released heme. Acquisition mechanisms that exploit the propensity of hemoglobin's β subunit to release heme likely represent a common strategy used by bacterial pathogens to obtain iron during infections.
Organizational Affiliation:
Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095.
