Fig. 3: STM0724 is the T1 Galf-PS polymerase and an ortholog of mycobacterial GlfT2. | Nature Communications

Fig. 3: STM0724 is the T1 Galf-PS polymerase and an ortholog of mycobacterial GlfT2.

From: Structure, biosynthesis and regulation of the T1 antigen, a phase-variable surface polysaccharide conserved in many Salmonella serovars

Fig. 3

a Crystal structure of Mycobacterium tuberculosis GlfT2 (pink)(PDB ID: 4fix) and AlphaFold model of STM0724 (blue)(Uniprot Q8ZQV0). The proteins share 21% sequence identity and have a Z-score of 32.5, with an rmsd of 3.3 Å. b HPLC traces of in vitro GT reactions containing STM0724, UDP-Galf (synthesized in situ by Glf from UDP-Galp) and acceptor compound 1. Reactions were performed for 1 h at 30 °C, stopped by the addition of an equal volume of acetonitrile, and the mixture analyzed by HPLC, using detection of the methoxybenzamide tag in the acceptor. The results from triplicate reactions were identical. Also shown is the product purified from large-scale reactions by gel filtration and SepPak elution. c NMR analysis of purified STM0724 product. The identity of the polymer is assigned on the HSQC spectrum and the linkage points of the sugars are shown on the HMBC spectrum. Sugars labeled X,Y and Z represent the reducing end and most of the chemical shifts converged onto the repeat unit. MB stands for methoxybenzamide. Chemical shifts are reported in Supplementary Table 2.

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