Gene Ontology annotation based on UniProtKB/Swiss-Prot keyword mapping
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Rz/Rz1 lysis gene equivalents in phages of Gram-negative hosts.
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Identified T4 pseT.3 (y13K) and pseT.2 (y13J) as Rz/Rz1-equivalent spanin genes and showed that their deletion in T4 results in a divalent cation-dependent lysis defect.
"In the case of T4, a deletion of a non-overlapping gene pair pseT.2 and pseT.3 identified as Rz/Rz1 equivalents resulted in the same divalent cation-dependent lysis phenotype."
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Defined spanins as periplasm-spanning proteins that physically connect the inner and outer membranes.
"These proteins were named "spanins," since their protein products are predicted to span the periplasm providing a physical connection between the inner and outer membranes."
Deep research summary for Bacteriophage T4 y13K
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Y13K (PseT.3) is the inner-membrane spanin (i-spanin) subunit of the T4 two-component spanin complex required for outer-membrane disruption during host cell lysis.
"**y13K/pseT.3 (UniProt P39504)** functions as the **i-spanin** subunit in the T4 spanin complex that is required for **outer-membrane disruption during the final step of host cell lysis**."
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Y13K carries an N-terminal transmembrane domain that anchors it in the host inner membrane with a periplasm-facing domain.
"**PseT.3 (y13K)** carries an **N-terminal transmembrane domain**, consistent with an **inner-membrane anchor** and a periplasm-facing domain."
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Deletion of pseT.3/pseT.2 in T4 produces a Mg2+-dependent lysis defect with spherical cells that fail to disrupt the outer membrane.
"A key defining experimental result is that deletion of the **non-overlapping gene pair pseT.3/pseT.2** in T4 produces the classical **divalent cation (Mg2+)-dependent lysis defect** known for λ Rz/Rz1 mutants: infected cells undergo PG removal but fail to complete OM disruption efficiently under Mg2+-supplemented conditions, forming **spherical** cells and yielding **small plaques**/plating defects."
UniProtKB entry P39504 (SPAN1_BPT4)
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Y13K is a component of the T4 spanin complex that disrupts the host outer membrane during viral exit.
"Component of the spanin complex that disrupts the host outer membrane and participates in cell lysis during virus exit."
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Y13K interacts via its C-terminus with the C-terminus of the outer lipoprotein spanin subunit across the periplasmic space.
"Interacts (via C-terminus) with the spanin outer lipoprotein subunit (via C-terminus). Part of the spanin complex which spans the entire periplasmic space."
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Y13K localizes to the host cell inner membrane as a single-pass type II membrane protein with its C-terminal domain on the periplasmic side.
"SUBCELLULAR LOCATION: Host cell inner membrane {ECO:0000250}; Single-pass type II membrane protein {ECO:0000250}; Periplasmic side {ECO:0000250}."