The basic keratin 10-binding domain of the virulence-associated pneumococcal serine-rich protein PsrP adopts a novel MSCRAMM fold.

Schulte T, Löfling J, Mikaelsson C, Kikhney A, Hentrich K, Diamante A, Ebel C, Normark S, Svergun D, Henriques-Normark B, Achour A

Open Biol 4 (-) 130090 [2014-01-15; online 2014-01-15]

Streptococcus pneumoniae is a major human pathogen, and a leading cause of disease and death worldwide. Pneumococcal invasive disease is triggered by initial asymptomatic colonization of the human upper respiratory tract. The pneumococcal serine-rich repeat protein (PsrP) is a lung-specific virulence factor whose functional binding region (BR) binds to keratin-10 (KRT10) and promotes pneumococcal biofilm formation through self-oligomerization. We present the crystal structure of the KRT10-binding domain of PsrP (BR187-385) determined to 2.0 Å resolution. BR187-385 adopts a novel variant of the DEv-IgG fold, typical for microbial surface components recognizing adhesive matrix molecules adhesins, despite very low sequence identity. An extended β-sheet on one side of the compressed, two-sided barrel presents a basic groove that possibly binds to the acidic helical rod domain of KRT10. Our study also demonstrates the importance of the other side of the barrel, formed by extensive well-ordered loops and stabilized by short β-strands, for interaction with KRT10.

Protein Science Facility (PSF)

PubMed 24430336

DOI 10.1098/rsob.130090

Crossref 10.1098/rsob.130090

pii: rsob.130090
pmc: PMC3909270
PDB: 3ZGH
PDB: 3ZGI