gltB

168

small subunit of [metabolite|glutamate] synthase

locus: BSU_18440

Molecular weight: 54.78 kDa

pI: 7.7

Protein length: 493 aa

Gene length: 1482 bp

function: [metabolite|glutamate] biosynthesis

product: [metabolite|glutamate] synthase (small subunit)

essential: no

ec: 1.4.1.13

synonyms: gltB

List of homologs in different organisms, belongs to COG0493 (Galperin et al., 2021)

Gene

Coordinates: 2,008,572  2,010,053

Phenotypes of a mutant

• auxotrophic for [metabolite|glutamate] [pubmed|38483038], can be bypassed by inactivation of [gene|A3A2EF3C95B833A11843553107D781EDEFF0BC41|citG] and [gene|146947C974D62BCB282BA3F5B924B35695D75886|ansR] (as a result of [gene|FED8E46AA1C4EFD27796D5DFBBB1663EBF336BFD|ansA]-[gene|5FAE80F22AEBAE63FC3C872EC651166A65C34DC2|ansB] derepression)[pubmed|38483038]

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The protein

Catalyzed reaction/ biological activity

• 2 L-[metabolite|glutamate] + [metabolite|NADP]⁺ --> [metabolite|2-oxoglutarate] + H⁺ + L-[metabolite|glutamine] + [metabolite|NADPH] (according to UniProt)

Protein family

• glutamate synthase family (with [protein|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA] and [protein|D1AF9DA2594D2E2A94DC207A870C8495954A7A17|yerD], according to UniProt)

[wiki|Domains]

• nucleotide binding domain ([metabolite|NADP]) (299313)

[wiki|Cofactors]

• two [metabolite|4Fe-4S] clusters [https://www.biorxiv.org/content/10.1101/2021.04.12.439528v1 reference]

Structure

• [PDB|2VDC] (the [protein|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[protein|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB] complex of ''Azospirillum brasiliense'') [Pubmed|18199747], note that B. subtilis [protein|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA] is unable to form dimers, thus [protein|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[protein|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB] exists as a heterodimer [pubmed|34931064]
• [PDB|7MFT] (the [protein|C36C8C9EEDCAD392D9BEC9728A1E0CBFF2F4E790|gudB]₆-([protein|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[protein|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB])₆ complex) [pubmed|34931064]
• [AF|O34399]

[wiki|Localization]

• cytoplasm (according to Swiss-Prot)

Expression and Regulation

Operons

• genes: [gene|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]

  description: [Pubmed|12823818]

  regulation

  • expressed in the presence of ammonium [Pubmed|11029411]

  regulatory mechanism

  • [protein|857EF1AC54DEA0690C01B7F8CEFFD16312C58F20|tnrA]: repression, [Pubmed|11029411], in [regulon|protein:857EF1AC54DEA0690C01B7F8CEFFD16312C58F20|tnrA regulon]
  • [protein|87BCAE725B02860156D50E1783F6DB68510C811E|gltC]: activation, [Pubmed|2548995], in [regulon|protein:87BCAE725B02860156D50E1783F6DB68510C811E|gltC regulon]
  • [protein|F899F1EE27E6D503BCC06BC52E3C7FD80B8EF725|fur]: indirect effect, in [regulon|protein:F899F1EE27E6D503BCC06BC52E3C7FD80B8EF725|fur regulon]

  sigma factors

  • [protein|360F48D576DE950DF79C1A2677B7A35A8D8CC30C|sigA]: sigma factor, [Pubmed|2548995], in [regulon|protein:360F48D576DE950DF79C1A2677B7A35A8D8CC30C|sigA regulon]

Other regulations

• [protein|CE542AE1A32CCD1ABB259E6159F7A37A8078E189|fsrA]: translation inhibition

Biological materials

Mutant

• BP123 (Δ[gene|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]::''ermC'') , available in [wiki|Fabian Commichau]'s lab
• GP807 (Δ[gene|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]-[gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]::''tet'') , available in [wiki|Jörg Stülke]'s lab
• GP517 (Δ[gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]::''ermC''), available in [wiki|Jörg Stülke]'s lab
• BKE18440 ([gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]::erm  trpC2) available at [http://bgsc.org/getdetail.php?bgscid=BKE18440 BGSC],  [Pubmed|28189581], upstream reverse: _UP1_CATGTTCCTCTCCCCTTCCT,  downstream forward: _UP4_TAAATAAAGGGGATTATCAT
• BKK18440 ([gene|AA07CC52B2DD48ACC9D3375E9D531CB1ACBE485A|gltB]::kan  trpC2) available at [http://bgsc.org/getdetail.php?bgscid=BKK18440 BGSC],  [Pubmed|28189581], upstream reverse: _UP1_CATGTTCCTCTCCCCTTCCT,  downstream forward: _UP4_TAAATAAAGGGGATTATCAT

Expression vectors

• pGP1119 (in [wiki|pGP380], for SPINE, expression in ''B. subtilis''), available in [wiki|Jörg Stülke]'s lab [pubmed|20933603]
• pGP3031: IPTG inducible expression, purification in ''E. coli'' with C-terminal His-tag, in [wiki|pGP574] (Strep-tag omitted), available in [wiki|Jörg Stülke]'s lab
• pGP3032: IPTG inducible expression, purification in ''E. coli'' with C-terminal Strep-tag, in [wiki|pGP574], available in [wiki|Jörg Stülke]'s lab

two-hybrid system

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

lacZ fusion

• see ''[gene|44DF1B7E476AD58B3CCC39300FFE0132D0D32AD0|gltA]

labs

• [wiki|Linc Sonenshein], Tufts University, Boston, MA, USA [http://www.tufts.edu/sackler/microbiology/faculty/sonenshein/index.html Homepage]
• [wiki|Fabian Commichau], Göttingen, Germany [http://www.uni-goettingen.de/de/413008.html homepage]

References

Reviews

• 16143852,12859215,22625175,12859215

Original Publications

• 27223617,12823818,20933603,11029411,7559360,15150225,2548995,17183217,17608797,17134717,14523131,12823818,18326565,18199747,22389480,25755103,28294562,29242163,34931064,38483038