UV-Visible Heme Absorbance Spectroscopic Characterization of Caenorhabditis elegans Globin Proteins GLB-10 and GLB-31
Description
In order to contribute to the limited body of knowledge about C. elegans globin proteins, we examined the heme absorbance of globin proteins GLB-10 and GLB-31 under oxygenated conditions using UV-Vis spectroscopy and used GLB-1 as a control. Each protein was overexpressed in E. coli and purified. Under oxygenated conditions, GLB-1 showed the expected spectrum with a Soret band at 414 nm, and Q bands at 543 nm and at 578 nm. GLB-10 showed a similar spectrum with a Soret band at 418 nm and Q bands at 546.8 nm and 574 nm. GLB-31 had a Soret band at 418 nm and Q bands at 540 nm and 570 nm. Structure data from the Research Collaboratory for Structural Bioinformatics Protein Data Bank (RCSB PDB) and AlphaFold were used to perform structure and sequence alignments of GLB-10, GLB-21, and GLB-31 with GLB-1 and GLB-6 with ChimeraX’s Matchmaker tool (Geuens et al. 2010, Yoon et al. 2010, Jumper et al. 2021, Varadi et al. 2024, Meng et al. 2023). Structurally, GLB-31 was the most similar to GLB-1 overall, with a root mean square deviation (RMSD) of 4.5 Å. However, the sequence alignment showed that GLB-21 had the most conserved residues when aligned with GLB-1, indicating that GLB-21 and GLB-1 have the most similar heme-coordinated residues. GLB-10 was the most similar to GLB-6 overall, with an RMSD of 3.8 Å. None of the experimental proteins had more than one His residue that was conserved from the GLB-6 alignment. As such, it was concluded that the experimental proteins are likely pentacoordinated proteins that have different functions.
Files
Steps to reproduce
See methods section in the PDF file.