Table 1 Characteristics of the signal peptides identified in the screening
Signal peptide | Amino acid sequence (putative cleavage site indicated by arrow) | Predicted function for corresponding protein | Length (amino acid) | Net charge of N-domain | Hydrophobicity (%) | Ala-X-Ala motif | Transmembrane helix |
|---|---|---|---|---|---|---|---|
Signal peptide with protease secretion | |||||||
 LP_23790 | MKKFNFKTMLLLVLASCVFGVVVNVTTSLGPQTTITAQA↓SK | transglycosylase | 39 | 3 | 59 | ✓ | ✓ |
 LP_08330 | MIKLRQVLKKILIVLMVFVLVFTAFSSSVDTVSA↓HR | hypothetical protein | 34 | 4 | 65 | ✓ | |
 LP_04240 | MKKLMCLFGVIGGLVFMSWTSPSIQATA↓TN | cell surface protein | 28 | 2 | 68 | ✓ | ✓ |
 LP_23670 | MQLLKRIMVIVGTLILGLQVSSVSGLA↓AS | cell surface protein | 27 | 2 | 70 | ✓ | |
 LP_28190 | MKRLRHIKLGMLLLSCLAFISMLAITSQA↓AA | extracellular protein | 29 | 4 | 62 | ✓ | |
 LP_29340 | MRKWQVAVVMLLAALGSWFAIGTQAQA↓KT | glutamine ABC transporter substrate binding, permease | 27 | 2 | 74 | ✓ | ✓ |
 LP_23680 | MPNKWWRLILGVMLVLSWAIPVRA↓AT | cell surface protein | 24 | 2 | 79 | ✓ | |
 LP_28170 | MKKMMRWLGAILVMISGLSAVVPAQA↓AN | cell surface protein | 26 | 3 | 77 | ✓ | ✓ |
 LP_23160 | MQKRLRLSLGMLLAVVASLLMMGQVASA↓DQ | hypothetical protein | 28 | 3 | 71 | ✓ | ✓ |
 LP_24320 | MRFAGKLKKVMIALVAAVTFSTAGLGIAGADLQAQA↓AS | D-alanyl-D-alanine carboxypeptidase | 36 | 4 | 72 | ✓ | ✓ |
 LP_14210 | MKKIVNWLLGSVLMIAAVTMLSSVSANA↓ST | hypothetical protein | 28 | 2 | 68 | ✓ | ✓ |
 LP_09710 | MRRLLTGTLVVGGLLLVVCLMAVNGQA↓KV | extracellular protein | 27 | 2 | 74 | ✓ | |
 PA_18600 | MVKSRNRILHYILVAVSVVIVVLGFSVIKASA↓HG | chitin-binding protein | 32 | 3 | 66 | ✓ | ✓ |
 PA_13510 | MYKGFKKYFSNGADRKAGNYPVAKRNKRWLLASAVMLAMFGAGMAQSHAFA↓KA | hypothetical protein | 51 | 9 | 59 | ✓ | ✓ |
 PA_18250 | MKLKAKLLLVVVPFLMGSVVYHPTPTVQA↓KT | DNA-entry nuclease | 29 | 3 | 69 | ✓ | |
 PA_08950 | MNQNWQKPSPKLNWVRFYSIVTILVLVTSVAGLEMLRVSA↓HQ | beta-lactamase class A | 40 | 3 | 58 | ✓ | |
 PA_17320 | MKKARWKLLLAGLALLGGISLGQNIISA↓NT | hypothetical protein | 28 | 4 | 71 | ✓ | |
 PA_10610 | MKRKWFSLLVAVFLIIGVAIGFGGILHSKSSG↓ND | hypothetical protein | 32 | 3 | 72 | ✓ | |
 PA_04150 | MKKAITTASFFLAIFVVFMVGSNAASA↓KS | hypothetical protein | 27 | 2 | 70 | ✓ | ✓ |
 PA_07000 | METKKRFKMYKSGKKWLVAAIVAGGIATAGSVASVNA↓DE | hypothetical protein | 38 | 7 | 59 | ✓ | |
Signal peptide without protease secretion | |||||||
 LP_27290 | MRRKLVGYMLSMLTVILALFMLGSTAHA↓KE | cell surface protein | 28 | 3 | 68 | ✓ | ✓ |
 LP_27220 | MKKINKLMILGMLVLGVTGATMINPEMTTA↓AH | extracellular protein | 30 | 3 | 67 | ✓ | |
 LP_17340 | MKKRFGWFLAIIVALIMTVVPLGQTQHAQA↓AD | ABC transporter substrate-binding and permease protein | 30 | 3 | 70 | ✓ | ✓ |
 LP_11950 | MTKRMSFKFKWVALVATLIVGIGSWQVLAHA↓DS | hypothetical protein | 31 | 4 | 68 | ✓ | ✓ |
 LP_12630 | MLKLIKQRLVWGLVLTATVSGVLSCNVAAHA↓TS | D-alanyl-D-alanine carboxypeptidase | 31 | 3 | 65 | ✓ | ✓ |
 LP_28330 | MKLSKRGLFWLLGLVSFAILLLFSQPLGAQA↓AT | cell surface protein | 31 | 3 | 74 | ✓ | ✓ |
 LP_27010 | MRKLIKACGLMVISMLVGLGIVTSALA↓AK | cell surface protein, CscB family | 27 | 3 | 74 | ✓ | ✓ |
 PA_14540 | MKNNKIIITAAIAGLLGGGVAYGGASFVQNRMEA↓TT | serine protease | 34 | 2 | 68 | ✓ | |
 PA_15330 | MNYRSILFTTAIATMGAFSFGHSPVSA↓HS | hydrolase | 27 | 1 | 59 | ||
Average (with protease secretion) | 31.5 | 3.4 | 68.2 | 50% with motif | 100% with helix | ||
Average (without protease secretion) | 29.9 | 2.8 | 68.1 | 67% with motif | 89% with helix | ||
t-test (with and without protease secretion) | 0.34 | 0.25 | 0.99 | – | – | ||