Analysis of the early heterocyst Cys-proteome in the multicellular cyanobacterium Nostoc punctiforme reveals novel insights into the division of labor within diazotrophic filaments

Table 2 Comparative functional characterization of quantified proteins

		24 h (Present study)							Steady-state[7]
Function		Total	>Het	% total	Equal	% total	>Fil	% total	Total	>Het	% total	Equal	% total	>Fil	% total
Adaptive metabolism	A	52	30	58	10	19	12	23	19	8	42	7	37	4	21
Core metabolism	C	292	43	15	76	26	173	59	236	60	25	87	37	89	38
Transport metabolism	T	16	5	31	9	56	2	13	13	7	54	5	38	1	8
Selfish metabolism	S	1	0	0	0	0	1	100	0	0	0	0	0	0	0
Unassigned metabolism	U	149	28	19	39	26	82	55	108	36	33	38	35	34	31
Not annotated	NA	1	0	0	0	0	1	100	1	1	100	0	0	0	0
Total		511	106	21	134	26	271	53	377	112	30	137	36	128	34
*Sub-function*
Adaptive metabolism
Carbon	A	3	0	0	1	33	2	67	1	0	0	0	0	1	100
Nitrogen	A	14	13	93	0	0	1	7	5	3	60	2	40	0	0
Development	A	16	15	94	1	6	0	0	3	2	67	1	33	0	0
Signal transduction	A	7	1	14	2	29	4	57	4	2	50	1	25	1	25
Stress	A	2	1	50	1	50	0	0	2	0	0	0	0	2	100
Taxis	A	1	0	0	0	0	1	100	0	0	0	0	0	0	0
Transcriptional regulation	A	6	0	0	5	83	1	17	2	1	50	1	50	0	0
Energy, monomer, polymer	A	2	0	0	0	0	2	100	2	0	0	2	100	0	0
Secondary	A	1	0	0	0	0	1	100	0	0	0	0	0	0	0
Core metabolism
Precursor	C	53	3	6	16	30	34	64	57	11	19	13	23	33	58
Cofactor	C	21	1	5	3	14	17	81	6	1	17	1	17	4	67
Energy	C	20	9	45	6	30	5	25	32	21	66	9	28	2	6
Monomers	C	54	5	9	4	7	45	83	23	1	4	10	43	12	52
Polymers	C	85	14	16	33	39	38	45	77	12	16	42	55	23	30
Cell envelope	C	29	11	38	5	17	13	45	20	6	30	6	30	8	40
Cell division	C	5	0	0	2	40	3	60	3	1	33	1	33	1	33
Reactive oxygen species/metabolic protection	C	15	0	0	4	27	11	73	15	7	47	3	20	5	33
Storage	C	10	0	0	3	30	7	70	3	0	0	2	67	1	33
Selfish metabolism
Phage	S	1	0	0	0	0	1	100	0	0	0	0	0	0	0
Transport metabolism
ABC systems	T	11	3	27	6	55	2	18	6	3	50	3	50	0	0
Ion ATPase	T	1	1	100	0	0	0	0	3	2	67	0	0	1	33
Export	T	3	0	0	3	100	0	0	4	2	50	2	50	0	0
Porter	T	1	1	100	0	0	0	0	0	0	0	0	0	0	0
Unassigned metabolism
Conserved hypothetical	U	81	16	20	21	26	44	54	57	21	37	18	32	18	32
Hypothetical	U	11	1	9	1	9	9	82	5	1	20	2	40	2	40
Unassigned	U	57	11	19	17	30	29	51	46	14	30	18	39	14	30
Not annotated	NA	1	0	0	0	0	1	100	1	1	100	0	0	0	0

The relative abundance levels of proteins in isolated heterocyst vs. their parental N₂-fixing filaments 24h (present study) and 6 days [7] after combined nitrogen step-down. The quantified proteins were grouped based on their functional annotation [27] and their relative differential abundance levels (using the Log₂ +/-0.678 thresholds of 1.6-fold). >Het (higher in heterocysts); >Fil (higher in filaments, i.e. vegetative cells) and Equal (even distribution) indicate the individual proteins cell-type specificity using the thresholds defined in the two studies.

ISSN: 1471-2164