ssbA

168

single-strand DNA-binding protein, part of the [wiki|replisome], promoter of [protein|search|RecA ]DNA repair center assembly, required to internalize and to recombine ssDNA with homologous resident duplex

locus: BSU_40900

Molecular weight: 18.60 kDa

pI: 4.82

Protein length: 172 aa

Gene length: 519 bp

function: [category|SW.3.1.1|DNA replication], [category|SW.3.1.5|DNA repair/ recombination]

product: single-strand DNA-binding protein

essential: yes

synonyms: ssbA, ssb

List of homologs in different organisms, belongs to COG0629 (Galperin et al., 2021)

Gene

Coordinates: 4,198,886  4,199,404

Phenotypes of a mutant

• essential [Pubmed|12682299]

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The protein

Catalyzed reaction/ biological activity

• SsbA inhibits ssDNA phosphorylase activity of [protein|64C6D783FF3F41C81B216F798A1DC8071345B1ED|pnpA] [Pubmed|21859751]
• SsbA co-assembles onto [protein|1CDF658441061EA476E27C2E60DEE45C4F45AC15|ssbB]-coated ssDNA [Pubmed|22373918]
• important for [protein|A44D4677FB70BE8F554BF1001A500F817C7DA95F|recA] DNA repair center assembly by recruiting [protein|80E6F156764FF30300D034EE6FB44F2DB8338AF3|recO] and [protein|BEBAF1EB53EBB3E7558BB5FE73C418B50000FA29|recR] to the [wiki|replisome] [Pubmed|24891441]
• [protein|A44D4677FB70BE8F554BF1001A500F817C7DA95F|recA]-ATP in concert with [protein|FC53216F600994C862F0C0D017C3FA28EB75DCB6|dprA] and [protein|8DE39680CA7663803A107066FBE9AFFCC77DB72A|ssbA] catalyzes DNA strand exchange, with [protein|1CDF658441061EA476E27C2E60DEE45C4F45AC15|ssbB] as an accessory factor [Pubmed|25138221]
• inhibits stable [protein|A44D4677FB70BE8F554BF1001A500F817C7DA95F|recA] nucleation and polymerization on ssDNA [pubmed|28911099]
• the [protein|8DE39680CA7663803A107066FBE9AFFCC77DB72A|ssbA]-[protein|FC53216F600994C862F0C0D017C3FA28EB75DCB6|dprA] mediator loads [protein|A44D4677FB70BE8F554BF1001A500F817C7DA95F|recA] onto any fragmented linear SPP1 ssDNA[pubmed|31876108]

[wiki|Domains]

• SSB domain (aa 1-104) (according to UniProt)

Structure

• [PDB|6BHX] (complex with ssDNA) [Pubmed|30472092]
• [PDB|6BHW] [Pubmed|30472092]
• [AF|P37455]

Modification

• phosphorylated on Arg-76 [Pubmed|22517742]
• phosphorylated on Tyr-82 by [protein|6100EA37592A2C31BC3DE79AD7948A8D6F65F6E1|ptkA], dephosphorylated by [protein|CF73D86DB024575BE8F043A4C3996458F4262E46|ptpZ] [Pubmed|16549871]

Effectors of protein activity

• Phosphorylation of Ssb increases binding to single-stranded DNA in vitro almost 200-fold [Pubmed|16549871]

Paralogous protein(s)

• [protein|1CDF658441061EA476E27C2E60DEE45C4F45AC15|ssbB]

[wiki|Localization]

• forms foci [Pubmed|21958350]
• Nucleoid (Mid-cell) [Pubmed|16479537]

Biological materials

two-hybrid system

• ''B. pertussis'' adenylate cyclase-based bacterial two hybrid system ([wiki|BACTH]), available in [wiki|Fabian Commichau]'s lab

References

Reviews

• 22976189,22933559,31950915,32286623

Original Publications

• 17853894,19730681,11948146,16479537,11948165,16549871,20122408,14762004,20581116,22054219,22373918,22517742,21859751,21170359,21958350,23268446,23536821,23779106,22383849,24310371,24443534,24891441,25138221,26707201,26786319,28575448,28878042,29059392,29059328,28911099,30472092,31876108,35234892,36901969