Structural Validation and Membrane Interaction Analysis of ORF104 (Oblin-2) in Streptococcus sanguinis.

This dataset provides the structural and topological validation of the micro-peptide ORF104 (Mexican Oblin-2), identified in Streptococcus sanguinis. It features a high-resolution 3D model generated by AlphaFold 3 (Model 0), revealing a well-defined amphipathic alpha-helix (residues 15-32) with a critical hydrophobic patch for membrane interaction. A comparative analysis between DeepTMHMM and HeliQuest is included, documenting a significant discrepancy between statistical predictors and molecular physics models. Notably, while DeepTMHMM suggests a globular cytoplasmic localization, this is likely a false negative due to the short length of the peptide (50 aa), a known limitation for machine-learning-based topology predictors. Conversely, the structural evidence from AlphaFold 3 and the hydrophobic moment calculated via HeliQuest strongly support a membrane-anchored functional role.