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![[Figure 2]](jb5052fig2mag.jpg)
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Figure 2
VcDciA and EcDnaC target the same binding site on DnaB helicases. (a) Sequence alignment of the LH and DH helices of VcDnaB and EcDnaB (generated by the EMBL–EBI Clustal Omega server; https://www.ebi.ac.uk/Tools/msa/clustalo/; Sievers et al., 2011  ) and displayed using the ESPript 3.0 server (https://espript.ibcp.fr; Robert & Gouet, 2014). The conserved residues are in white on a red background. An orange asterisk marks the conserved tryptophan residues, while a black asterisk marks the specific serine/glycine residues in the DH helix. (b) Close-up view of the interaction interface forming a three- or five-helix bundle between the two-helix LH–DH module of DnaB (blue and green) and VcDciA (top; magenta and yellow; PDB entry 8a3v; this study) or EcDnaC NTD (bottom; magenta; PDB entry 6qel), respectively. The tryptophans whose intrinsic fluorescence variation was measured in the Tycho experiments are shown in orange sticks. (c, d) Tycho NT.6 analysis. The emission profile of a tryptophan is shifted to the red when it is released to the solvent during thermal denaturing of the protein. The 350/330 nm ratios measured for the different helicase-loader mixtures are reported in red and the predicted ratio in the absence of interaction is reported in black. The ratio comparisons are reported for each helicase-loader couple indicated, namely VcDnaB (c) or EcDnaB (d) with two constructs of VcDciA or EcDnaC. The curves correspond to the mean ± SEM of three to five analyses. The Tycho interaction analysis between VcDnaB and VcDciA has previously been published (Marsin et al., 2021) but is reproduced here (indicated by *) for easy evaluation with other helicase-loader couples. |
![[Figure 2]](jb5052fig2.jpg)
 | STRUCTURAL BIOLOGY |
ISSN: 2059-7983
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