Table 1

Identified proteins from Daphnia pulex acclimated to 10°C or 20°C

Spot no.

Specificity N10: N20

Matched peptide sequences

Sequence coveragea)

Mascot scoreb)

Mrgel/Mrpredicted

pI gel/pI predicted

SP Length

PP Length

Putative function (symbolic name)


Proteolytic enzymes


36

0.3*

1. VVAGEHSLR

2. SVDVPVVDDDTCNR

8.9%

149

30/26–29

4.4/4.4–4.8

15

27

Trypsin (TRY5L)

1. LTAAEEPTRVEIR

2. IRNDVALIK

7.5%

80

30/25–30

4.4/4.5–5.3

18

48

Chymotrypsin (CHY1A)


37

0.2*

1. GVTDLTIFR

2. VVAGEHSLR

3. VVAGEHSLRTDSGLEQNR

9.8%

159

29/26–29

4.4/4.4–4.8

15

27

Trypsin (TRY5F)

1. VVAGEHSLR

2. SVDVPVVDDDTCNR

8.9%

149

29/26–29

4.4/4.4–4.8

15

27

Trypsin (TRY5L)


38

0.5*

1. GLADADIAVFK

2. LIWMGQYNR

3. YYRDELAGK

10.7%

123

29/30

4.5/4.5

19

Endoribonuclease-like protein (ERNA)

1. GLADADIAVFK

2. LIWMGQYNR

3. YYRDELAGK

8.0%

123

29/39

4.5/4.6

20

Endoribonuclease-like protein (ERNB)

1. VVAGEHSLR

2. SVDVPVVDDDTCNR

8.9%

149

29/26–29

4.5/4.4–4.8

15

27

Trypsin (TRY5L)

1. GVTDLTIFR

2. VVAGEHSLR

6.5%

80

29/26–29

4.5/4.4–4.8

15

27

Trypsin (TRY5F)


39

0.4*

1. VVAGEHSLR

2. SVDVPVVDDDTCNR

8.9%

149

29/26–29

4.6/4.4–4.8

15

27

Trypsin (TRY5L)

1. GVTDLTIFR

2. VVAGEHSLR

6.5%

120

29/26–29

4.6/4.4–4.8

15

27

Trypsin (TRY5F)


40

0.6*

1. TTEEYYVSVQK

2. TGGGCYSYIGR

6.5%

112

25/23–27

4.5/4.7–4.6

?

39 ?

Astacin (ACN2)

1. GVTDLTIFR

2. VVAGEHSLR

6.5%

109

25/26–29

4.5/4.4–4.8

15

27

Trypsin (TRY5F)


41

0.4*

1. LTAAEEPTR

2. LTAAEEPTRVEVR

3. IINDVALIK

9.1%

141

25/25–30

4.7/4.4–5.0

18

47

Chymotrypsin (CHY1C)


28

1.2

see [12]

Peptidase M13

Peptidase M2

Carboxylesterase, type B

Sphingomyelin phosphodiesterase

Sphingomyelin phosphodiesterase


31

0.6

see [12]

30/34–45

30/35–46

29/26–29

4.8/4.9–4.8

4.8/5.1–4.9

4.4/4.4–4.8

16

16

15

92

93

27

Carboxypeptidase A (CPA1A)

Carboxypeptidase A (CPA1B)

Trypsin (TRY5F)


32

0.3

see [12]

23/24–27

5.0/5.2–5.4

17

24

Trypsin (TRY4B)


Egg yolk proteins & precursors


43

7.3*

see Figure 2

/190–220

/6.4–6.7

17–20

Vitellogenin (VTG1, VTG2, VTG4)


44

7.1*

see Figure 3

see Figure 2

15.7%

2.8%

271

25/42

25/220

5.8/5.3

5.8/6.7

17

17

Actin

Vitellogenin (VTG1)


45

5.9*

see Figure 2

2.2%

132

21/190

5.2/6.4

20

Vitellogenin (VTG4)


46

5.2*

see Figure 2

2.9%

361

21/220

5.9/6.7

17

Vitellogenin (VTG1)


47

4.9*

see Figure 3

see Figure 2

9.6%

2.0%

25/42

25/220

5.6/5.3

5.6/6.7

17

Actin

Vitellogenin (VTG1, VTG2)

1. EDQMDYLEEK

2. LLVEKER

3. YSVDEELNK

3.6%

25/83

5.6/4.7

HSP90


49

4.4*

see Figure 2

?.?%

???

21/190–220

4.8/6.4–6.7

17–20

Vitellogenin (VTG1, VTG2, VTG4)


50

4.2*

see Figure 2

2.2%

163

20/220

5.7/6.7

17

Vitellogenin (VTG1)


52

3.7

see Figure 2

3.0%

344

18/220

5.1/6.7

17

Vitellogenin (VTG1, VTG2)


Cytoskeleton & muscle proteins


48

4.5*

see Figure 2

see Figure 3

?.?%

???

27/42

5.2/5.3

Actin

Vitellogenin (VTG4)

1. EQLDEESEAK

2. AEELEDAKR

3. ATVLANQMEK

27/220

5.2/5.9

Myosin heavy chain (MHC-1)

1. LTTDPAFLEK

2. NAAAVHEIR

3. GDLGIEIPPEK

27/??

5.2/?

Pyruvate kinase


51

3.6*

see Figure 3

?.?%

???

36/42

5.7/5.3

Actin


ATPase


42

9.8*

2. GNEDLSTAILK

3. MDELQLFK

4. GDIFIVR

5. KQLALIK

6. EMVELPLR

5.1%

214

16/89

5.3/5.0

AAA+ ATPase


Carbohydrate-modifying enzymes


35

1.2

see [12]

α-Amylase (AMY)


34

1.0

see [12]

Exo-β-1,3-Glucanase (EXG5)


1

0.4

see [12]

Cellubiohydrolase (CEL7A)


29

0.3

see [12]

Endo-β-1,4-Glucanase (CEL9A)

Paramyosin (PMY)


30

0.6

see [12]

Endo-β-1,4-Mannanase (MAN5A)

β-1,3-Glucan-binding protein


19

0.6

see [12]

Enolase (ENO)


Identification was based on 2D gel electrophoresis and nano-HPLC-ESI-MS/MS analysis of trypsin-digested proteins matched against the "Frozen Gene Catalog" of the D. pulex protein database [2]. The compiled information includes the spot number (Figure 1A, B), the 10-to-20°C expression ratio, the number and sequences of matched peptides, the sequence coverage, the Mascot score as a statistical measure of identification probability, the experimental and theoretical molecular weight (Mr) and isolectric point (pI) of the mature protein (without signal peptide), the predicted length of the N-terminal signal peptide (SP) in secretory proteins, as well as the putative function and symbolic name of the protein. The length of the putative pro-peptide (PP) is additionally provided for proteolytic enzymes that are secrected as inactive precursors (zymogens). The predicted Mr and pI values of zymogens and the mature enzymes are given as value ranges. The amino acid sequences of the identified proteins were derived from the gene models listed in Table 2. a)percentage of predicted protein sequence covered by matched peptides. b)Probability-based MOWSE score: -10*Log(P), where P is the probability that the observed match is a random event. Scores >38 indicate identity or extensive homology (p < 0.05). Protein scores are derived from ions scores as a non-probabilistic basis for ranking protein hits. The Mascot-score calculation was performed using whole-protein sequence (including the N-terminal signal peptide in case of extracellular proteins). *p < 0.05 (t-Test).

Schwerin et al. BMC Physiology 2009 9:8   doi:10.1186/1472-6793-9-8

Open Data