| Gene/protein | Synonyms | Organism / identifier | Location in virion | Role in assembly / morphogenesis | Known interaction partners / assembly context | Quantitative data | Key supporting sources (year; URL) |
|---|---|---|---|---|---|---|---|
| gene 48 product gp48 | Baseplate tail-tube junction protein gp48; baseplate-tube cap; gene product 48 | *Enterobacteria phage T4*; UniProt P13339 | Baseplate–tail tube junction; attached at the top of the hub / external interface between wedges and hub; part of the platform at the proximal end of the tail tube (pqac-00000000, pqac-00000001, pqac-00000003, pqac-00000005, pqac-00000008) | Structural tube-initiator / adapter, not an enzyme; gp48 is added late in baseplate assembly together with gp54 to complete the baseplate and create the platform that nucleates tail-tube polymerization by gp19 and supports subsequent sheath assembly by gp18 (pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000005) | Directly/functionally associated with gp54; required before gp19 tube polymerization; located near gp25 (sheath assembly initiator) and linked to hub/wedge structures; recent T4 structural work places gp48 at the bottom end of the tape-measure protein (gp29/TMP) tube where it connects the inner tube to the baseplate (pqac-00000002, pqac-00000003, pqac-00000005, pqac-00000007) | Monomer mass ~39.7 kDa; stoichiometry 6 copies per tail/baseplate; after sequential addition of six gp48 and six gp54, 144 gp19 monomers polymerize to form the tail tube; T4 tail length ~98 nm in the classical assembly study (pqac-00000000, pqac-00000001, pqac-00000002, pqac-00000008) | Leiman et al., 2010, *Virology Journal* — https://doi.org/10.1186/1743-422X-7-355 ; Leiman et al., 2003, *Cell Mol Life Sci* — https://doi.org/10.1007/s00018-003-3072-1 ; Ishimoto et al., 1988, *Virology* — https://doi.org/10.1016/0042-6822(88)90622-8 ; Yap & Rossmann, 2014, *Future Microbiology* — https://doi.org/10.2217/fmb.14.91 ; Taylor et al., 2018, *Mol Microbiol* — https://doi.org/10.1111/mmi.13921 ; Rao, 2024, recent T4 structural study cited in retrieved context (pqac-00000000, pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000005, pqac-00000007) |


*Table: This table compiles the main functional annotation facts for Enterobacteria phage T4 gp48 (gene 48; UniProt P13339), including localization, assembly role, interaction partners, and quantitative stoichiometric data. It is useful as a compact evidence-backed reference for the protein’s structural role in T4 tail morphogenesis.*