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. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: J Am Soc Mass Spectrom. 2015 Apr 8;26(7):1128–1142. doi: 10.1007/s13361-015-1109-y

Figure 4.

Figure 4

The effects of proline on neutral loss. a) Comparison of the spectra of doubly-protonated TXHVITEANpSGPR where X=P in the top panel and X=Y in the bottom panel. For lettering: blue denotes y-ions, green denotes b-ions, and red denotes losses from the precursor. For ion markers: black denotes no neutral loss, red denotes loss of H3PO4, blue denotes loss of water or ammonia, purple denotes loss of H3PO4 and water or ammonia. b) Comparison of the spectra of doubly protonated DEIXpSFALQ where X=P in the top panel and X=A in the bottom panel. c) Representation of the increased chances of peptides from the ISB dataset being in the lowest tercile of neutral loss, given that there is a proline at the indicated position relative to the phosphosite. The y-axis is in units of log2 of the enrichment. Error bars represent the 95% confidence interval for the mean.