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Publication Abstract from PubMed

Streptococcus groups A and B cause serious infections, including early onset sepsis and meningitis in newborns. Rib domain-containing surface proteins are found associated with invasive strains and elicit protective immunity in animal models. Yet, despite their apparent importance in infection, the structure of the Rib domain was previously unknown. Structures of single Rib domains of differing length reveal a rare case of domain atrophy through deletion of 2 core antiparallel strands, resulting in the loss of an entire sheet of the beta-sandwich from an immunoglobulin-like fold. Previously, observed variation in the number of Rib domains within these bacterial cell wall-attached proteins has been suggested as a mechanism of immune evasion. Here, the structure of tandem domains, combined with molecular dynamics simulations and small angle X-ray scattering, suggests that variability in Rib domain number would result in differential projection of an N-terminal host-colonization domain from the bacterial surface. The identification of 2 further structures where the typical B-D-E immunoglobulin beta-sheet is replaced with an alpha-helix further confirms the extensive structural malleability of the Rib domain.

Defining the remarkable structural malleability of a bacterial surface protein Rib domain implicated in infection.,Whelan F, Lafita A, Griffiths SC, Cooper REM, Whittingham JL, Turkenburg JP, Manfield IW, St John AN, Paci E, Bateman A, Potts JR Proc Natl Acad Sci U S A. 2019 Dec 9. pii: 1911776116. doi:, 10.1073/pnas.1911776116. PMID:31818940^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.