Computing Exact p-values for a Cross-correlation Shotgun Proteomics Score Function

Computing exact p-values for a cross-correlation shotgun proteomics score function.

The core of every protein mass spectrometry analysis pipeline is a function that assesses the quality of a match between an observed spectrum and a candidate peptide. We describe a procedure for computing exact p-values for the oldest and still widely used score function, SEQUEST XCorr. The procedure uses dynamic programming to enumerate efficiently the full distribution of scores for all possi...

Computing exact P-values for DNA motifs

MOTIVATION Many heuristic algorithms have been designed to approximate P-values of DNA motifs described by position weight matrices, for evaluating their statistical significance. They often significantly deviate from the true P-value by orders of magnitude. Exact P-value computation is needed for ranking the motifs. Furthermore, surprisingly, the complexity of the problem is unknown. RESULTS...

Computing exact p - values for DNA motifs ( Part I )

Motivation: Many heuristic algorithms have been designed to approximate p-values of DNA motifs described by position weight matrices, for evaluating their statistical significance. They often significantly deviate from the true p-value by orders of magnitude. Exact p-value computation is needed for ranking the motifs. Furthermore, surprisingly, the complexity of the

Computing highly accurate or exact P-values using importance sampling

Perfluorooctanoic Acid for Shotgun Proteomics

Here, we describe the novel use of a volatile surfactant, perfluorooctanoic acid (PFOA), for shotgun proteomics. PFOA was found to solubilize membrane proteins as effectively as sodium dodecyl sulfate (SDS). PFOA concentrations up to 0.5% (w/v) did not significantly inhibit trypsin activity. The unique features of PFOA allowed us to develop a single-tube shotgun proteomics method that used all ...