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.2 (y13J) and pseT.3 (y13K) as Rz/Rz1-equivalent spanin genes and showed that their deletion in T4 causes 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 lysis proteins that span the periplasm to 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 y13J
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Y13J (PseT.2) is the outer membrane lipoprotein subunit (o-spanin) of the T4 two-component spanin complex.
"**Best-supported function:** **o-spanin (outer membrane lipoprotein subunit) required for outer membrane disruption in lysis**, acting together with its partner i-spanin (pseT.3) as a **two-component spanin complex**."
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Deletion of pseT.3 and pseT.2 in T4 causes a Mg2+-dependent lysis defect in which infected cells become spherical due to failure of outer-membrane disruption.
"A constructed **Δ(pseT.3 pseT.2)** mutant showed a classic spanin-null phenotype described as **Mg2+-dependent lysis defect** with infected cells adopting a **spherical morphology**—consistent with successful PG degradation but failure to disrupt the OM barrier."
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Y13J is synthesized as a lipoprotein precursor processed by signal peptidase II and anchored to the outer membrane.
"**Expected localization:** As an o-spanin, y13J/pseT.2 is expected to be an **outer membrane-anchored lipoprotein**, produced as a precursor and processed by signal peptidase II at the lipobox and lipidated at the N-terminal cysteine."
UniProtKB entry P39503 (SPAN2_BPT4)
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Y13J 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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Y13J interacts via its C-terminus with the C-terminus of the inner membrane spanin subunit to span the periplasmic space.
"Interacts (via C-terminus) with the spanin inner membrane subunit (via C-terminus). Part of the spanin complex which spans the entire periplasmic space."
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Y13J is lipid-anchored to the periplasmic side of the host cell outer membrane.
"SUBCELLULAR LOCATION: Host cell outer membrane {ECO:0000250}; Lipid-anchor {ECO:0000250}; Periplasmic side {ECO:0000250}."