Identity. ParB/Spo0J-family centromere-binding protein, the first annotated gene of KT2440,
next to parA and oriC. NCBI WP_003253185.1 "MULTISPECIES: ParB/RepB/Spo0J family partition
protein [Pseudomonas]", named from SPARCLE architecture 11445026. UniProt Swiss-Prot entry with a
curated "by similarity" function [file:PSEPK/parB/parB-uniprot.txt "Binds to the DNA origin of
replication (By similarity)."].
Domains and motifs. ParB_N (ParB/Srx fold, CTP-binding; PF02195), HTH_ParB (PF17762), ParB_C
dimerisation (PF23552); TIGR00180. CTP-binding box GERRWRA at 91-97, identical in P. aeruginosa
ParB (79% identity overall) [file:PSEPK/parA/parA-bioinformatics/RESULTS.md].
P. putida evidence. parA and parB mutants give 5-10% anucleate cells in M9 at the transition
to stationary phase PMID:11832517. ParAB stabilises a parS-carrying mini-F in E. coli, and three
parS-like sequences lie in the oriC-parAB region PMID:11849535.
CTPase. ParB proteins are CTP-dependent clamps [PMID:31649139 "We show that ParB is an enzyme
that hydrolyzes cytidine triphosphate (CTP) to cytidine diphosphate (CDP)."; PMID:31835030;
PMID:32077854 "show that CTP is required for spreading"]. P. aeruginosa ParB has been assayed
directly PMID:38843873. CTP
dependence is ancestral in the family PMID:41448349. Proposed NEW CTPase activity (ISO), and NEW
sequence-specific DNA binding (ISO) to record the evidence behind the DNA binding MODIFY.
Sporulation. The GOA (TreeGrafter) term positive regulation of sporulation is inherited from
B. subtilis Spo0J. P. putida does not sporulate PMID:11849535. REMOVE.
Related P. putida paper. A ParB-like CTPase clamp, BisD, drives gene activation in P. putida
transfer competence (PMID:40842242). BisD is a separate protein of the ICE-associated
ParB-like family, not PP_0001.
NCBI/CDD comparison. The architecture gives only DNA binding. TIGR00180 also matches and
carries chromosome segregation, cytokinesis and DNA binding, but under winner-take-all only the
naming source passes on GO, so chromosome segregation is lost. The CDD region note still calls the
N-terminal domain a "ParB-like nuclease domain".