1. BG-11 medium
& cells
0.45 μm syringe filter
Filled with NaOH pellets
Cotton plug
Syringe tube
Figure S1.

2. Figure S2. MW (kDa) 12C (1.1% 13C) 10.8% 13C 49.6% 13C 98% 13C 250
150
100 75
Band selected for in-gel digestion 50
MW (kDa) 37 25 20 15 10
Figure S2.

3. Figure S3.

4. Synechococcus elongatus PCC 7942
ν 3
ν 2
ν 1
Synechocystis sp. PCC 6803
Synechococcus elongatus PCC 7942
Raman shift (cm-1)
Intensity
10.8% 13C
25.3% 13C
49.6% 13C
73.8% 13C
98% 13C
12C (with natural 13C abundance 1.1%)
Figure S4.

5. PCA result of RR spectra of Synechocystis sp. PCC 6803 single cells
12C (with natural 13C abundance 1.1%)
10.8% 13C
25.3% 13C
49.6% 13C
73.8% 13C
98% 13C

6. PCA result of RR spectra of Synechococcus elongatus PCC 7942 single cellsB
12C (with natural 13C abundance 1.1%)
49.6% 13C
98% 13C
Figure S5.

7. Figure S6 Theoretical isotopic cluster distributions of the peptide
768.9
765.4
769.9
769.4
782.5
795.5
768.4
770.4
781.5
765.9
783.5
795.0
796.0
767.9
770.9
780.5
784.5
771.4
766.4
766.9
794.5
766.4
767.4
771.9
779.5
796.5
785.5
Intensity
772.4
794.0
765.9
772.9
766.9
773.4
778.4
786.5
767.4
777.4
793.5
797.0
792.5
793.0
797.5
m/z, Da
m/z, Da
m/z, Da
m/z, Da
Isotopic cluster distributions of the peptide
769.4
765.4
768.9
782.5
795.5
765.9
768.4
769.9
781.5
796.0
765.50
766.50
767.50
766
769
772
778
782
786
783.5
795.0
770.4
792
795
767.9
780.5
770.9
794.5
784.5
766.4
767.4
796.5
779.5
Intensity
771.4
794.0
785.5
766.9
771.9
793.5
766.9
778.4
765.4
766.4
772.4
765.9
772.9
777.4
786.5
792.0
792.5
793.0
797.0
767.4
773.4
791.5
797.5
m/z, Da
m/z, Da
m/z, Da
m/z, Da
Figure S6