Download MendeleyAn M protein coiled coil unfurls and exposes its hydrophobic core to capture LL-37
Kolesinski, P., Wang, K.C., Hirose, Y., Nizet, V., Ghosh, P., Stallings, C.L., Dotsch, V.(2022) Elife 11
- PubMed: 35726694
- DOI: https://doi.org/10.7554/eLife.77989
- Primary Citation of Related Structures:
7SAF, 7SAY - PubMed Abstract:
Surface-associated, coiled-coil M proteins of Streptococcus pyogenes (Strep A) disable human immunity through interaction with select proteins. However, coiled coils lack features typical of protein-protein interaction sites, and it is therefore challenging to understand how M proteins achieve specific binding, for example, with the human antimicrobial peptide LL-37, leading to its neutralization. The crystal structure of a complex of LL-37 with M87 protein, an antigenic M protein variant from a strain that is an emerging threat, revealed a novel interaction mode. The M87 coiled coil unfurled and asymmetrically exposed its hydrophobic core to capture LL-37. A single LL-37 molecule was bound by M87 in the crystal, but in solution additional LL-37 molecules were recruited, consistent with a 'protein trap' neutralization mechanism. The interaction mode visualized crystallographically was verified to contribute significantly to LL-37 resistance in an M87 Strep A strain and was identified to be conserved in a number of other M protein types that are prevalent in human populations. Our results provide specific detail for therapeutic inhibition of LL-37 neutralization by M proteins.
Organizational Affiliation:
Department of Chemistry & Biochemistry, University of California, San Diego, La Jolla, United States.
