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Roper, D.

Publications and source records attributed to Roper, D..

2 recordsLinked to original sources
bioRxiv2020

Structure-function analyses of dual-BON domain protein DolP identifies phospholipid binding as a new mechanism for protein localisation

The Gram-negative outer membrane envelops the bacterium and functions as a permeability barrier against antibiotics, detergents and environmental stresses. Some virulence factors serve to maintain the integrity of the outer membrane, including DolP (formerly YraP) a protein of unresolved structure and function. Here we reveal DolP is a lipoprotein functionally conserved among Gram-negative bacteria and that loss of DolP increases membrane fluidity. We present the NMR solution structure for DolP, which is composed of two BON domains that form an interconnected opposing pair. The C-terminal BON domain binds to anionic phospholipids through an extensive membrane:protein interface providing evidence of subcellular localization of these phospholipids within the outer membrane. This interaction is essential for DolP function and is required for sub-cellular localization of the protein to the cell division site. The structure of DolP provides a new target for developing therapies that disrupt the integrity of the bacterial cell envelope.

biochemistry↗
bioRxiv2020

Structure-based modelling and dynamics of MurM, a Streptococcus pneumoniae penicillin resistance determinant that functions at the cytoplasmic membrane interface

MurM is an aminoacyl-tRNA dependant ligase that aminoacylates the Lipid II peptidoglycan precursor, in the human pathogen Streptococcus pneumoniae. MurM is required for the generation of branched peptidoglycan precursors enabling indirect cross-links in the peptidoglycan and is found to be essential for penicillin resistance. In this study we have solved the X-ray crystal structure of Staphylococcus aureus FemX, an isofunctional homologue of MurM, and used this as a template to generate a homology model of MurM. Using this model, we perform molecular docking and molecular dynamics to examine the interaction of the protein with the phospholipid bilayer and the membrane embedded Lipid II substrate of MurM. Our model suggests that MurM is associated with the major membrane phospholipid cardiolipin, and we confirm this with experimental evidence that the activity of MurM is enhanced by this phospholipid and inhibited by its direct precursor phosphatidylglycerol. This suggests that the spatial association of pneumococcal membrane phospholipids and their impact on MurM activity may be a critical to the final architecture of the peptidoglycan and the expression of clinically relevant penicillin resistance in this pathogen.

biochemistry↗