TABLE 2.
T5 structural proteins identified by LC-MS/MS and Edman N-terminal sequencinga
| Gene | ORF no. a/b/c | Band name | Molecular mass (kDa) | LC-MS/MS % coverage | Processing | Function/location | Reference(s) |
|---|---|---|---|---|---|---|---|
| Capsid | |||||||
| T5p144/T5.148/ORF137 | p144M | 19.3 | 44 | No | Head completion | This study | |
| D20 | T5p145/T5.149/ORF138 | pb8P,M | 32.8 | N: K159 (Ed.) | Major head protein | 8, 9 | |
| T5p146/T5.150/ORF139 | pb11P,M | 15.8 | 64 | Head protease | 10; this study | ||
| N5 | T5p147/T5.151/ORF140 | pb10M | 17.3 | 62 | C: S1264 | Decoration | 8, 9 |
| T5p148/T5.152/ORF141 | pb7P,M | 43.8 | N: K10 (Ed.) | Portal | 8, 9; this study | ||
| Tail | |||||||
| ltf | T5p131/T5.133/ORF124 | pb1 | 148.0 | 33 | C: S1264 | L-shaped fibers | 12–14; this study |
| T5p132/—/ORF125 | p132 | 15.0 | 84 | No | L-fibers/tail tip collar | This study | |
| D17 | T5p133/T5.137/ORF126 | pb4 | 74.9 | Central straight fiber | This study | ||
| D16 | T5p134/T5.138/ORF127 | pb3 | 107.3 | 26 | Baseplate hub protein | This study | |
| T5p135/T5.139/ORF128 | pb9 | 22.7 | 69 | No | Distal tail protein | This study; 56 | |
| D18/19 | T5p136/T5.140/ORF129 | pb2 | 121.9 | 47 | C: V1148 ±2 | Tape measure protein | 15, 16 |
| T5p140/T5.144/ORF133 | p140 | 34.5 | 47 | No | This study | ||
| N4 | T5p141/T5.145/ORF134 | pb6 | 50.3 | Tail tube protein | 8, 9 | ||
| T5p142/T5.146/ORF135 | p142 | 18.4 | 38 | No | Tail terminator | This study | |
| T5p143/T5.147/ORF136 | p143 | 27.8 | 57 | No | Tail completion | This study | |
| oad | T5p153/T5.157/ORF141 | pb5 | 67.8 | No | Receptor binding protein | 17, 19–23 |
Proteins identified in previous studies are indicated with their gene name according to the first mapping of T5 genes (34) and with their band name according to the SDS-PAGE analysis published in reference 8. All proteins are indicated with their ORF numbers in the sequences of the T5 genome deposited in GenBank: a, T5st0 deletion mutant (AY692264); b, T5 wild-type strain from Pushchino collection (AY543070); c, T5 strain ATCC 11303-B5 (AY587007). For the capsid proteins, P or M indicates that they were found in proheads II or in mature capsids, respectively. Processing sites were determined from protein coverage in MS or N-terminal sequencing by Edman degradation (Ed.). When sequence coverage included both N- and C-terminal ends of the protein, no processing was mentioned (No). In the absence of specific indication, we assumed that the protein is not processed due to the agreement between the apparent molecular mass determined on SDS-PAGE and the mass predicted from the corresponding ORF. —, not annotated.