Table 2.
Counts of Sco transport proteins according to substrate type
|
Substrate |
No. of proteins of indicated type acting on substrate type |
||||||||
|---|---|---|---|---|---|---|---|---|---|
| Channels/Pores | Primary Carriers | Secondary Carriers | Group translocators | Transmembrane electron flow carriers | Auxiliary proteins | (Putative) Poorly characterized | Total no. of systems | ||
|
I. Inorganic Molecules |
|
|
|
|
|
|
|
|
|
| A. |
Nonselective |
5 |
|
1 |
|
|
|
|
6 |
| B. |
Cations |
9 |
33 |
32 |
|
|
|
15 |
89 |
| C. |
Anions |
|
6 |
15 |
|
|
|
|
21 |
| D. |
Electrons |
|
29 |
2 |
|
9 |
|
|
40 |
|
II. Carbon sources |
|
|
|
|
|
|
|
|
|
| A. |
Sugars & polyols |
2 |
83 |
9 |
2 |
|
|
|
96 |
| B. |
Monocarboxylates |
|
11 |
15 |
|
|
|
|
26 |
| C. |
Di- & tricarboxylates |
|
|
7 |
|
|
|
|
7 |
| D. |
Organoanions (noncarboxylic) |
|
2 |
6 |
|
|
|
|
8 |
| E. |
Aromatic Compounds |
|
|
8 |
|
|
|
|
8 |
|
III. Amino acids & their derivatives |
|
|
|
|
|
|
|
|
|
| A. |
Amino acids & conjugates |
1 |
16 |
39 |
|
|
|
|
56 |
| B. |
Amines, amides, polyamines, & organocations |
1 |
5 |
7 |
2 |
|
|
|
15 |
| C. |
Peptides |
|
20 |
1 |
|
|
|
|
21 |
|
IV. Vitamins, cofactors & cofactor precursors |
|
|
|
|
|
|
|
|
|
| A. |
Vitamins & vitamin or cofactor precursors |
|
5 |
3 |
1 |
|
|
|
9 |
| B. |
Enzyme & redox cofactors |
|
|
|
|
|
|
|
0 |
| C. |
Siderophores; siderophore-Fe complexes |
|
21 |
8 |
|
|
|
|
29 |
|
V. Drugs, dyes, sterols & toxins |
|
|
|
|
|
|
|
|
|
| A. |
Multiple drugs |
|
20 |
36 |
|
|
|
|
56 |
| B. |
Specific drugs |
|
4 |
58 |
|
|
|
|
62 |
| C. |
Pigments |
|
7 |
1 |
|
|
|
|
8 |
| D. |
Other hydrophobic substances |
|
6 |
|
|
|
|
|
6 |
|
VI. Macromolecules |
|
|
|
|
|
|
|
|
|
| A. |
Carbohydrates |
1 |
16 |
|
|
|
1 |
|
18 |
| B. |
Proteins |
1 |
10 |
|
|
|
3 |
3 |
17 |
| C. |
Lipids |
|
14 |
7 |
1 |
|
|
|
22 |
|
VII. Nucleic acids |
|
|
|
|
|
|
|
|
|
| A. |
Nucleic acids |
|
10 |
8 |
1 |
|
|
2 |
21 |
|
VIII. Unknown |
|
|
|
|
|
|
|
|
|
| A. |
Unknown |
|
3 |
14 |
|
|
|
|
17 |
| Total | 20 | 321 | 277 | 7 | 9 | 4 | 20 | 658 | |
Substrate categories include: (I) inorganic molecules; (II) carbon sources; (III) amino acids & their derivatives; (IV) vitamins, cofactors & cofactor precursors; (V) drugs, dyes, sterols & toxins; (VI) macromolecules; (VII) nucleic acids; and (VIII) unknown.