Fig. 6: Elongation of the glycan strand.
From: Structural basis of peptidoglycan synthesis by E. coli RodA-PBP2 complex
Modelling of the different steps that occur during elongation of the glycan strand. Starting from the left RodA-PBP2 is shown in complex with two Lipid II molecules. Once these two molecules are connected through the GT activity of RodA, Und-PP is released from cavity A either between TM helix 7 and the core of RodA, or under the JM helices into the membrane. We have modelled RodA-PBP2 bound sequentially to Lipid II, Lipid IV, up to Lipid XXII, and here we show different complexes during the elongation until the glycan chain reaches the active site of PBP2. RodA-PBP2 is shown as surface representation in grey. The previously suggested opening and closing of the head and anchor domain of PBP2 upon binding of the regulator protein MreC is not modelled here15,23,24,87. The Und-PP lipid is represented in black sticks and the disaccharides with the pentapeptide stem attached as sticks in different colors.
