Over the years, genetic profiling of the gut microbiome of patients with colorectal cancer (CRC) using genome sequencing has suggested over-representation of several bacterial taxa. However, little is known about the protein or metabolite secretions from the microbiota that could lead to CRC pathology. Proteomic studies on the role of microbial secretome in CRC are relatively rare. Here, we report the identification of proteins from Schizosaccharomyces pombe found in the stool samples of both healthy individuals and patients with CRC. We found that distinctive sets of S. pombe proteins were present exclusively and in high intensities in each group. Our finding may trigger a new interest in the role of gut mycobiota in carcinogenesis.
Proteins of the DUF866 superfamily are exclusively found in eukaryotic cells. A member of the DUF866 superfamily, C1ORF123, is a human protein found in the open reading frame 123 of chromosome 1. The physiological role of C1ORF123 is yet to be determined. The only available protein structure of the DUF866 family shares just 26% sequence similarity and does not contain a zinc binding motif. Here, we present the crystal structure of the recombinant human C1ORF123 protein (rC1ORF123). The structure has a 2-fold internal symmetry dividing the monomeric protein into two mirrored halves that comprise of distinct electrostatic potential. The N-terminal half of rC1ORF123 includes a zinc-binding domain interacting with a zinc ion near to a potential ligand binding cavity. Functional studies of human C1ORF123 and its homologue in the fission yeast Schizosaccharomyces pombe (SpEss1) point to a role of DUF866 protein in mitochondrial oxidative phosphorylation.