Table 1. Phosphorylation sites within CnaA and CnaB subunits identified by TiO₂ enrichment and LC-MS/MS analysis.

Protein	Peptide Sequencea	Phosphorylated Residue	m/z	Charge	Mass Error (ppm)	Mascot Ion Scoreb	Ascore Localization Probabilityc
CnaA	EELEDETPTSV[pS]PSAPSPPLPMDVESSEFK	S408	1104.4843	3	−1.6	46	99%
CnaA	EELEDETPT[pS]V[pS]PSAPSPPLPMDVESSEFK	S406, S408	1131.1415	3	−2.1	54	80%, 80%
CnaA	EELEDETPTSVSP[pS]AP[pS]PPLPMDVESSEFK	S410, S413	1131.1415	3	−0.5	75	90%, 99%
CnaA	EELEDETPT[pS]VSPSAPSPPLPMDVESSEFKR	S406	1156.5159	3	−3.4	94	90%
CnaA	RI[pS]MSAGSGR	S537	551.2449	2	−4.2	72	99%
CnaA	RI[pS]MSAG[pS]GR	S537, S542	591.2272	2	−5.3	66	99%, 99%
CnaB	RA[pS]VGTSQLLDNIV[pS]ASNFDRDEVDR	S21, S33	1008.7813	3	−5.5	94	99%, 99%
CnaB	RA[pS]VGTSQLLDNIVSASNFDRDEVDR	S21	982.1329	3	1.5	106	99%

^a[pS] indicates phosphorylated residue.

^bMascot identity score of >41 indicates identity or extensive homology (p<0.05).

^cProbability of phosphorylated residue localization based on Ascore algorithm.

CnaA subunit and CnaB subunit peptides contained uniquely identified phosphorylation residues or combinations of phosphorylation residues. Due to the proximity of multiple phosphorylatable residues within these peptides, mass spectra from each identification were submitted to an independent algorithm (Ascore) which assigns confidences to the localization of each phosphorylation.