Protein Family Models

ParB is a component of the par system which mediates accurate DNA partition during cell division. It recognises A-box and B-box DNA motifs. ParB forms an asymmetric dimer with 2 extended helix-turn-helix (HTH) motifs that bind to A-boxes. The HTH motifs emanate from a beta sheet coiled coil DNA binding module [1]. Both DNA binding elements are free to rotate around a flexible linker, this enables them to bind to complex arrays of A- and B-box elements on adjacent DNA arms of the looped partition site [1]. [1]. 16306995. Structures of ParB bound to DNA reveal mechanism of partition. complex formation.. Schumacher MA, Funnell BE;. Nature. 2005;438:516-519. (from Pfam)

Date:

2024-08-14

Proteins containing this domain include Escherichia coli plasmid protein ParB and mammalian Sulfiredoxin-1. ParB is involved in chromosome partition. It localises to both poles of the predivisional cell following completion of DNA replication [1]. Sulfiredoxin-1 contributes to oxidative stress resistance by reducing cysteine-sulfinic acid formed under exposure to oxidants in the peroxiredoxins PRDX1, PRDX2, PRDX3 and PRDX4 [2]. [1]. 12603730. Productive interaction between the chromosome partitioning. proteins, ParA and ParB, is required for the progression of the. cell cycle in Caulobacter crescentus.. Figge RM, Easter J, Gober JW;. Mol Microbiol. 2003;47:1225-1237.. [2]. 15448164. Characterization of mammalian sulfiredoxin and its reactivation. of hyperoxidized peroxiredoxin through reduction of cysteine. sulfinic acid in the active site to cysteine.. Chang TS, Jeong W, Woo HA, Lee SM, Park S, Rhee SG;. J Biol Chem. 2004;279:50994-51001. (from Pfam)

Date:

2024-08-14

This HMM represents the most well-conserved core of a set of chromosomal and plasmid partition proteins related to ParB, including Spo0J, RepB, and SopB. Spo0J has been shown to bind a specific DNA sequence that, when introduced into a plasmid, can serve as partition site. Study of RepB, which has nicking-closing activity, suggests that it forms a transient protein-DNA covalent intermediate during the strand transfer reaction.

Date:

2021-04-27