| Aspect | Evidence summary | Key citations with DOI/URL and year |
|---|---|---|
| Identity/size/oligomerization | T4 gene product 10 (gp10; UniProt P10928) is a baseplate wedge protein of bacteriophage T4. It is 602 aa long and forms a trimer; structural studies place gp10 as a peripheral wedge/pin element in the baseplate. Crystal structures of the C-terminal fragment and cryo-EM fitting support a trimeric, elongated architecture about 210 Å long and ~60 Å in diameter. (pqac-00000008, pqac-00000012, pqac-00000026, pqac-00000029) | Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Leiman et al., 2006, J Mol Biol, doi:10.1016/j.jmb.2006.02.058, https://doi.org/10.1016/j.jmb.2006.02.058; Arisaka et al., 2016, Biophys Rev, doi:10.1007/s12551-016-0230-x, https://doi.org/10.1007/s12551-016-0230-x; Kostyuchenko et al., 2003, Nat Struct Biol, doi:10.1038/nsb970, https://doi.org/10.1038/nsb970 |
| Copy number | Reviews and structural summaries report gp10 stoichiometry as 18 copies per virion tail, corresponding to 3 copies per wedge in a six-wedge baseplate. Cryo-EM density/volume analysis is consistent with a gp10 trimer plus one gp7 per wedge region. (pqac-00000024, pqac-00000026, pqac-00000027, pqac-00000029) | Arisaka et al., 2016, Biophys Rev, doi:10.1007/s12551-016-0230-x, https://doi.org/10.1007/s12551-016-0230-x; Arisaka & Kanamaru, 2013, Biophys Rev, doi:10.1007/s12551-013-0114-2, https://doi.org/10.1007/s12551-013-0114-2; Kostyuchenko et al., 2003, Nat Struct Biol, doi:10.1038/nsb970, https://doi.org/10.1038/nsb970 |
| Domain architecture | Gp10 is a four-domain trimeric protein. Domain I (residues 1–143) contains an N-terminal trimeric coiled coil (residues 1–39) and a prism/β-barrel region; domain II is a prism-like adaptor for short tail fibers gp12; domain III is a three-finger-like module providing the gp11 attachment site; domain IV (residues ~406–602) was crystallized and fitted into cryo-EM density. The domains have non-collinear threefold axes that reorient during baseplate rearrangement. Structural homology links gp10 to gp11 and gp12, and the N-terminus shows sequence similarity to gp9. (pqac-00000008, pqac-00000009, pqac-00000010, pqac-00000012) | Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Leiman et al., 2006, J Mol Biol, doi:10.1016/j.jmb.2006.02.058, https://doi.org/10.1016/j.jmb.2006.02.058 |
| Key interaction partners | Experimentally supported interactions include strong binding to gp11 and gp7, followed by incorporation of gp8 and gp6 during wedge maturation. Domain II binds short tail fibers gp12; domain III provides the gp11 attachment site; domain IV contacts gp7 and, in the star state, gp9. In the 2003 baseplate reconstruction, gp10 sits clamped between gp11 fingers and contacts the N-terminus of one gp12. Protease protection shows gp10 becomes resistant when bound to gp7. (pqac-00000000, pqac-00000001, pqac-00000006, pqac-00000008, pqac-00000019, pqac-00000029) | Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Arisaka & Kanamaru, 2013, Biophys Rev, doi:10.1007/s12551-013-0114-2, https://doi.org/10.1007/s12551-013-0114-2; Yap et al., 2010, Macromol Biosci, doi:10.1002/mabi.201000042, https://doi.org/10.1002/mabi.201000042; Leiman et al., 2006, J Mol Biol, doi:10.1016/j.jmb.2006.02.058, https://doi.org/10.1016/j.jmb.2006.02.058; Kostyuchenko et al., 2003, Nat Struct Biol, doi:10.1038/nsb970, https://doi.org/10.1038/nsb970 |
| Role in wedge/baseplate assembly | Gp10 is an early wedge protein and part of the wedge initiation complex with gp11. Assembly proceeds sequentially through gp10–gp11, gp10–gp7, gp10–gp7–gp8, gp10–gp7–gp8–gp6, then gp53 and gp25. Reported sedimentation coefficients include gp11–gp10 9.7S, gp10–gp7 10.2S, gp10–gp7–gp8 12.1S, gp10–gp7–gp8–gp6 14.5S, gp10–gp7–gp8–gp6–gp53 15.0S, and gp10–gp7–gp8–gp6–gp53–gp25 15.3S; gp53 addition can drive assembly into a 43.7S star-shaped baseplate-like structure. The assembled T4 baseplate is a six-wedge, dome-like particle around a central hub; one early cryo-EM reconstruction measured the baseplate at ~520 Å diameter and ~270 Å long. (pqac-00000005, pqac-00000006, pqac-00000024, pqac-00000027, pqac-00000030) | Yap et al., 2010, J Mol Biol, doi:10.1016/j.jmb.2009.10.071, https://doi.org/10.1016/j.jmb.2009.10.071; Yap et al., 2010, Macromol Biosci, doi:10.1002/mabi.201000042, https://doi.org/10.1002/mabi.201000042; Arisaka & Kanamaru, 2013, Biophys Rev, doi:10.1007/s12551-013-0114-2, https://doi.org/10.1007/s12551-013-0114-2; Arisaka et al., 2016, Biophys Rev, doi:10.1007/s12551-016-0230-x, https://doi.org/10.1007/s12551-016-0230-x; Kostyuchenko et al., 2003, Nat Struct Biol, doi:10.1038/nsb970, https://doi.org/10.1038/nsb970 |
| Role in dome→star transition and sheath contraction triggering | Gp10 is not an enzyme; its primary function is structural and signaling-related within the baseplate. During the pre-attachment dome to post-attachment star transition, gp10 changes orientation and interaction partners. The whole gp10 rotates by ~100° about its long axis, and domain IV rotates by ~60°; gp10 loses interaction with gp12 and gains contact with gp9 while maintaining linkage to gp7. The gp7–gp10 covalent linkage is reported as important for maintaining baseplate structure during the conformational switch. The baseplate acts as the signaling center that transmits host-recognition information to trigger sheath contraction; gp10 is positioned at junctions connecting gp7, gp11, gp12, and gp9, so it participates in signal propagation rather than serving as the sole trigger. Cryo-EM captured pre- and post-attachment states at 4.11 Å and 6.77 Å; in vitro star-shaped wedge/baseplate maps reached 3.8 Å. (pqac-00000012, pqac-00000016, pqac-00000019, pqac-00000021, pqac-00000022, pqac-00000023) | Leiman et al., 2006, J Mol Biol, doi:10.1016/j.jmb.2006.02.058, https://doi.org/10.1016/j.jmb.2006.02.058; Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Taylor et al., 2016, Nature, doi:10.1038/nature17971, https://doi.org/10.1038/nature17971 |
| Experimental methods/evidence types | Evidence comes from cryo-EM reconstructions of intact and in vitro-assembled baseplates, X-ray crystallography of gp10 fragments, fitting of atomic structures into cryo-EM maps, analytical ultracentrifugation/sedimentation velocity, gel filtration/SEC, His-tag pulldown and affinity isolation of assembly intermediates, SDS-PAGE, protease-sensitivity/protection assays, and comparative structural analysis. Key quantitative readouts include 3.8 Å cryo-EM for the in vitro assembled star-shaped baseplate-like complex, 4.11 Å and 6.77 Å for pre-/post-attachment baseplates, and multiple s-values for wedge intermediates. (pqac-00000005, pqac-00000006, pqac-00000008, pqac-00000015, pqac-00000022) | Yap et al., 2010, J Mol Biol, doi:10.1016/j.jmb.2009.10.071, https://doi.org/10.1016/j.jmb.2009.10.071; Yap et al., 2010, Macromol Biosci, doi:10.1002/mabi.201000042, https://doi.org/10.1002/mabi.201000042; Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Taylor et al., 2016, Nature, doi:10.1038/nature17971, https://doi.org/10.1038/nature17971 |
| Functional annotation takeaway | The best-supported annotation for T4 gp10 is: trimeric baseplate wedge protein that nucleates and stabilizes wedge assembly with gp7/gp11, provides attachment interfaces for gp11 and short tail fibers gp12, contacts gp9 in the activated state, and contributes mechanically to the baseplate conformational switch that initiates downstream tail sheath contraction during infection. Its localization is extracellular, in the mature virion tail baseplate at the distal end of the phage particle. (pqac-00000008, pqac-00000016, pqac-00000024, pqac-00000026) | Yap et al., 2016, PNAS, doi:10.1073/pnas.1601654113, https://doi.org/10.1073/pnas.1601654113; Arisaka et al., 2016, Biophys Rev, doi:10.1007/s12551-016-0230-x, https://doi.org/10.1007/s12551-016-0230-x |


*Table: This table summarizes the main functional-annotation evidence for bacteriophage T4 gp10 (UniProt P10928), including structure, stoichiometry, interaction partners, assembly pathway, and role in baseplate activation. It is useful as a compact evidence matrix linking specific mechanistic claims to the primary structural and biochemical literature.*