Validation of Shewanella oneidensis MR-1 Small Proteins by AMT Tag-based Proteome Analysis
Using stringent criteria for protein identification by accurate mass and time (AMT) tag mass spectrometric methodology, we detected 36 proteins <101 amino acids in length, including 10 that were annotated as hypothetical proteins, in 172 global tryptic digests of Shewanella oneidensis MR-1 proteins analyzed. Peptides that map to the conserved, but functionally uncharacterized proteins SO4134 and SO2787, were the most frequently detected small proteins in these samples, while hypotheticals SO2669 and SO2063, conserved hypotheticals SO0335 and SO2176, and the SlyX protein (SO1063) were observed at frequencies similar to small expected abundant ribosomal proteins and translation initiation factor IF-1 and consequently, likely to encode important cellular functions. In addition, 30 proteins including three of the small proteins that map to genes predicted to encode frameshifts, point mutations, or recoding signals were detected. Of these 30 genes, peptides that map to positions beyond internal stop codons were detected in 13 genes (SO0101, SO0419, SO0590, SO0738, SO1113, SO1211, SO3079, SO3130, SO3240, SO4231, SO4328, SO4422, and SO4657). While expression of the full-length formate dehydrogenase encoded by SO0101 can be explained by incorporation of selenocysteine at the internal stop codon, the mechanism of translating downstream sequences in the remaining genes remains unknown.
- Research Organization:
- Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-76RL01830
- OSTI ID:
- 15020907
- Report Number(s):
- PNNL-SA-42691; KP1102010; TRN: US200521%%424
- Journal Information:
- OMICS. A Journal of Integrative Biology, Vol. 8, Issue 3
- Country of Publication:
- United States
- Language:
- English
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