Table S1.

Time course of oxidative modifications of D1 and D2 proteins

Protein	0 min	15 min	30 min
D1	316T +go*	316T+go	1M+to
	317W+do,go	317W+do, go, kyn	7R+ca
	319D+go	328M+go	130E+go
	328M+go	331M+go	131W+go
	331M+go	332H+go	315N+go
	333E+go		316T+go
			317W+do, go, kyn
			319D+go
			329E+go
			331M+go
			332H+go
			333E+go
D2	18M+go	18M+go	18M+go
	246M+go	246M,+go	242E+de
	247V+go	247V+go	244Y+go
	329M+go	328W+go,	245S+go
		329M+go, do 333D+go	246M+go
		334Q+go	247V+go
		336H+hro	328W+do, kyn 329M+do, go, to
			333D+gam
			341F+go
			342P+go
			343E+ca, de
			344E+de, go
			345V+go

^*Oxidative modifications key: do, double oxidation, +31.99 Da; gam, Glu/Asp decarboxylation, −30.01 Da; go, general oxidation, +15.99 Da; hro, histidine ring opening, −10.03 Da; kyn, kynurenine formation, +3.99 Da; to, triple oxidation, +47.98 Da. In some instances, more than one type of modification was observed for a particular amino acid residue on different identified peptides, these are separated by commas. It should be noted that whereas a total of 12 different types of oxidative modifications were incorporated into the MassMatrix searches, only these 6 types were actually observed in this study.