IndraLab
Statements
|
49
45
sparser
"The structure of SLO-bound NADase 193-451,G330D superimposes well with the structure of NADase 193-451 in complex with IFS (PDB 4KT6), with a root-mean-square deviation (RMSD) of 0.518 Å for 212 aligned C α atoms, suggesting the common polymorphism G330D does not affect the global structure of the NADase enzymatic domain (Supplementary Fig. xref )."
sparser
"To evaluate the impact of the NADase-SLO interaction on GAS cytotoxicity, we first assessed the contribution of the salt-bridge to NADase translocation into host cells during bacterium-host cell interaction via SLO-mediated translocation known as CMT xref ; an essential step for GAS to exert its full cytotoxic potential."
sparser
"The atomic details of the NADase 193-451,G330D /SLO 106-574 complex determined by X-ray crystallography in this study (Figs. xref and xref ) allow us to design experiments to evaluate the importance of specific NADase-SLO interactions in GAS virulence by introducing point mutations in the GAS genome rather than gene deletion."
reach
"A20 exhibited a higher level of NADase translocation than A20 during GAS-A549 infection (Fig. 4e), demonstrating the salt bridge at the NADase/SLO complex interface plays a key role in NADase translocation.To study the impact of the complex-defective mutation on GAS resistance to phagocytic killing, differentiated U937 cells were infected with A20, A20 , or A20 at an MOI of 50, and the bacterial survival inside phagocytic cells was assessed (Fig. 4f)."
reach
"Moreover, it is suggested that direct interaction and mutual stabilization between NADase and SLO are crucial for enhancing GAS virulence , signifying the importance of the NADase/SLO complex formation in GAS pathogenesis.NADase and SLO are functionally-interdependent during GAS infection."
reach
"However, NADase remains a potent virulence factor and is able to interact with SLO similarly to the wild type , suggesting the molecular evolution of NADase has a tendency for preservation of the NADase/SLO complex.The synergistic activities of NADase and SLO through physical association is a unique example among Gram-positive bacteria, as secreted toxins generally function exclusively."
reach
"The overall structure of the NADase /SLO heterodimer exhibits an elongated shape with the C-terminal domain 4 of SLO bound to the C-terminal enzymatic domain of NADase.The structure of SLO-bound NADase superimposes well with the structure of NADase in complex with IFS (PDB 4KT6), with a root-mean-square deviation (RMSD) of 0."
reach
"Overall, SAXS studies reveal functionally-relevant conformations of the NADase/SLO complex and suggest the dynamic interplay between SLO and NADase is fundamental to the functioning of the complex and the molecular clues provided here will be beneficial for future studies to dissect the mechanistic actions of NADase and SLO in CMT.Taken together, this work delivers structural insight into the synergism of NADase and SLO in GAS pathogenesis and fills a current knowledge gap in the literature."
reach
"In addition to SAXS studies, we attempted to visualize each protein within the NADase/SLO complex by SANS with contrast variation, where the measurements were designed such that SLO would be contrast matched in 42% D O and the deuterium labelled NADase would be contrast matched in 100% D O."
reach
"The column was calibrated with proteins of standard masses, and the Stokes radius of NADase alone and the NADase and SLO complex were determined to be consistent with globular protein masses of 59.5 kDa (predicted molecular mass, 47.2 kDa) and 136.3 kDa (predicted molecular mass of SLO + NADase, 110kDa), respectively."
reach
"Thus, the SANS provides additional support that the NADase/SLO complex exhibits dynamic behavior, involving a rigid NADase/SLO core structure with dynamic peripheral domains.The multistate ensemble of the NADase/SLO complex shows two distinct conformations adopted by the SLO N-terminal disordered region and the NADase N-terminal domain."
reach
"As the dissociation process of a protein complex often occurs through a number of transition events involving low surface area contact interfaces , the compact-to-extended state transition could be interpreted as the first step of the dissociation process of the NADase/SLO complex."
reach
"This may suggest that the dynamic motions of the N-terminal domain of NADase and the N-terminal disordered region of SLO are functionally linked to the CMT activity which involves the separation of NADase from SLO.Mapping the polymorphic residues of NADase identified from clinical isolates on the full-length structural model of the NADase/SLO complex reveals the polymorphisms are distant from the complex interface (Supplementary Fig. 8a), supporting the notion that the preservation of the NADase/SLO complex plays an important role in the molecular evolution of NADase ."
reach
"Additionally, structural analyses on the full-length atomistic models of the NADase/SLO complex suggest that both compact and extended states are competent in NADase-mediated glycan-binding (Supplementary Fig. 8b) and that the interface interaction is conserved in the molecular evolution of NADase (Supplementary Fig. 8a)."
reach
"Our studies convey the structure-functional relationship of the NADase/SLO complex underpinning the augmented virulence of GAS.For over a decade, the biological relevance of the NADase-SLO interaction in GAS pathogenesis could only be demonstrated by deletion of either toxin or both due to the lack of structural information."