Extended Data Fig. 2: DltX is a predicted bitopic transmembrane protein with an extracellular C-terminus and is required for DltD to copurify with DltB.
From: Mechanism of d-alanine transfer to teichoic acids shows how bacteria acylate cell envelope polymers
a, (top) The TOPCONS web server66 for consensus-based membrane protein topology prediction was used to predict the topology of S. aureus DltX. The sequence of S. aureus DltX is shown with the predicted localization of each individual residue indicated beneath. (bottom) An AlphaFold240 model of S. aureus DltX generated using ColabFold41. This specific model is from an overall model of DltX with DltD and was selected here because it illustrates the topology of the protein well. We note that in the DltDX model, DltX’s predicted topology is in agreement with the known topology31 of DltD. b, An α-myc western blot indicates that a similar amount of myc-StDltD was present in the solubilized membranes loaded onto the TALON immobilized metal affinity chromatography (IMAC) resin during purifications of StDltB-His10 (and interactors) from E. coli cells expressing StdltB and StdltD, with or without StdltX. A similar amount of myc-StDltD was also present in the flow-through from the resin in the two samples. However, no myc-StDltD could be observed in the IMAC elution fraction from the sample derived from E. coli cells that did not express StdltX.
