Journal: bioRxiv

Article Title: Cryo-EM structure of MutL-activated MutH

doi: 10.64898/2026.04.21.719898

Figure Lengend Snippet: (A) Structure of the MutL-MutH-DNA complex. MutL LN40 is coloured in light and dark green, MutH in purple, and the DNA in orange. (B) Structure of MutL LN40 bound to a 5′ extended single stranded DNA (PDB ID: 7P8V). In this structure, the single-stranded DNA overhang is located in the same groove as MutH in the MutL-MutH-DNA complex, indicting that MutL LN40 cannot bind MutH and DNA simultaneously. (C) Superposition of three MutL LN40 structures in different functional states: apo, ssDNA-bound, and MutH-bound. The changes in the groove between the two monomers are highlighted by helices 265–281 and 313–331. The width of the groove ranges from 14 Å in the ssDNA-bound structure (blue, PDB ID: 7P8V), to 21 Å in the apo structure (orange, PDB ID: 1B63), to 28 Å in the MutH-bound structure (green, this work. (D) Conservation analysis of MutH from H. influenzae and E. coli mapped onto the E. coli MutH structure. Highly conserved residues are shown in magenta, and lesser conserved residues in blue. The strong conservation of the DNA-binding site supports the use of the available H. influenzae MutH-DNA structure (PDB ID: 2AOR) as a structural reference for comparison with our E. coli MutL-bound MutH complex.

Article Snippet: All proteins were expressed in E. coli BL21(DE3) cells grown in 2x YT media (Formedium, UK) at 30 °C.

Techniques: Functional Assay, Binding Assay, Comparison

Journal: bioRxiv

Article Title: Bioprospecting Novel Luciferase Genes from Museum Coleoptera

doi: 10.64898/2026.04.21.719859

Figure Lengend Snippet: The plasmid pET16b containing the Costa Rica Fluc gene was used to transform E. coli BL21 (DE3) and the colonies were transferred to nitrocellulose, induced with IPTG and screened with luciferin. Bioluminescence was detected on a PhotonIMAGER Optima and the bioluminescent intensity displayed from blue (low intensity) to red (high intensity). The bioluminescent activity of the plated transformants from the primary screen over a 20 second intergral is shown in (A). In (B) randomly picked colonies from the primary screen, were screened for bioluminescent activity. Images were produced using M3 Vision software and the intensity scaling between (A) and (B) is not directly comparable.

Article Snippet: A gene encoding the proposed Costa Rica Fluc was designed as codon optimised for E. coli and was synthesized by IDT and incorporated into a pET16b vector (Sigma-Aldrich) to enable transformation of E. coli BL21 (DE3) competent cells (Fisher Scientific).

Techniques: Plasmid Preparation, Activity Assay, Produced, Software