Mass Spectrometric Analysis of Differentially Expressed Proteins in an Endangered Medicinal Herb, Picrorhiza kurroa

Table 1

Differentially expressed proteins identified from MALDI-TOF/TOF MS data using MASCOT search engine.

Band number	Protein identified	Accession number	M.W. (Da)	% Seq. Coverage	SCORE	e-value	Functions
1	Methionine sulfoxide reductase	XP_003594067	15,446	29	54	0.062	Methionine sulfoxides can be reduced back to the methionines by a thioredoxin-dependent enzyme, peptide methionine sulfoxide reductase (Msr), providing cells with a mechanism to repair proteins damaged by reactive oxygen species rather than having them degraded and then resynthesizing them de novo.
2	Ferredoxin-6	NP_001147617	15,334	14	60	0.045	It uses iron-sulfur proteins as electron donors and NAD^+ or NADP^+ as electron acceptors. These function primarily in photosynthesis where they transfer electrons from photoreduced photosystem I to ferredoxin NADP (+) reductase in which NADPH is produced for CO2 assimilation.
3	40S ribosomal protein S13-1	Q69UI2	17,105	46	59	0.048	Is involved in protein translation.
4	Peptidyl-prolyl cis-trans isomerase	P35627	18,320	27	55	0.058	Peptidyl-prolyl cis-trans isomerases have been termed conformases or rotamases because they catalyse slow steps in the initial folding/rearrangement of proteins.
5	Rab GTPase B1C isoform 2	EOY29043	21,168	43	52	0.069	Key players of vesicular transport. They act as molecular switches regulating the fusion of vesicles with target membranes through the conformational change between GTP- and GDP-bound forms.
6	DnaJ homolog subfamily C member 28-like	XP_004497574	22,904	40	54	0.062	Play central roles in the heat stress. Act as cochaperone along with DnaK in the DnaK-DnaJ system. DnaJ is able to act as a chaperone on its own, but its main role is as cochaperone interacting with DnaK.
7	Glyceraldehyde-3-phosphate dehydrogenase	ABD37966	34,541	20	68	0.026	Enzyme of the glycolytic pathway responsible for the conversion of glyceraldehyde 3-phosphate to D glycerate-1, 3,-bisphosphate. It also acts as reversible metabolic switch under oxidative stress.
8	1-Aminocyclopropane-1-carboxylate oxidase	XP_002532366	38,381	25	56	0.056	Plays an important role in regulation of ethylene formation in plants in response to various stress conditions.
10	1-Acyl-sn-glycerol-3-phosphate acyltransferase 2-like	XP_004136588	43,818	17	61	0.042	It is a key enzyme of phospholipid and triglyceride biosynthesis. Several lines of evidence suggest that AGPAT should play a key role in the synthesis of phospholipids/triglycerides required for permeability barrier homeostasis.
11	Photosystem I reaction center subunit V, chloroplast precursor	XP_002949489	13,343	30	72	0.018	Encodes subunit G of photosystem I, an 11 kDa membrane protein that plays an important role in electron transport between plastocyanin and PSI and is involved in the stability of the PSI complex. It also takes part in cyclic photophosphorylation resulting in ATP production without NADPH generation.
12	2-oxoglutarate ferrous-dependent oxygenase	ADY80557	20,760	27	52	0.068	The 2-oxoglutarate (2-OG) and ferrous iron dependent oxygenases are a superfamily of enzymes that catalyse a wide range of reactions including hydroxylations, desaturations, and oxidative ring closures. 2-OG oxygenases catalyse reactions in the posttranslational modification of collagens and in the biosynthesis of both primary and secondary metabolites. They have also been identified as catalysing steps in the biosynthesis of plant signalling molecules including ethylene and the gibberellins.
13	Predicted: ethylene-responsive transcription factor WIN1-like	XP_004152351	21,950	33	57	0.053	Promotes cuticle formation by inducing the expression of enzymes involved in wax biosynthesis. Confers drought resistance. Acts as a transcriptional activator. Binds to the GCC-box pathogenesis-related promoter element.
14	UbiE/COQ5 methyltransferase	XP_003078783	24,603	36	66	0.033	Involved in ubiquinone biosynthesis.
15	Putative cytochrome P450 superfamily protein	AFW88279	23,550	25	64	0.038	Cytochrome P450 (CYP) enzymes are a superfamily of monooxygenases that are found in all kingdoms of life and which show extraordinary diversity in their reaction chemistry. Important for the biosynthesis of several compounds, such as hormones, defensive compounds, and fatty acid conjugates.
16	NADH dehydrogenase subunit F	ABB93079	27,880	28	52	0.068	Catalyses the transfer of electrons from NADH to coenzyme Q (CoQ). It is the “entry enzyme” of oxidative phosphorylation in the mitochondria.
17	Mitochondrial carrier family	XP_002502691	29,524	36	59	0.048	Solute carriers in the inner mitochondrial membrane which connect the internal metabolism with that of the surrounding cell. It is known to catalyse the specific transport of various substrates, such as nucleotides, amino acids, dicarboxylates, cofactors, phosphate, or H^+.
18	Adenylate isopentenyl transferase 8	Q9LJL4	37,583	23	67	0.029	Involved in cytokinin biosynthesis. Catalyzes the transfer of an isopentenyl group from dimethylallyl diphosphate (DMAPP) to ATP and ADP.
20	Chaperone protein DnaJ-like	XP_002274349	48,696	13	55	0.058	Members of the DnaJ-like protein family act as chaperones through direct interaction with different Hsp70 acting in protein pairs that appear to be specifically adapted to each other.
21	3-Ketoacyl-CoA synthase 11-like isoform 1	XP_004251584	57,764	12	60	0.045	Contributes to cuticular wax and suberin biosynthesis. Involved in both decarbonylation and acyl-reduction wax synthesis pathways.