Obg

• Description: GTP-binding protein involved in initiation of sporulation and assembly of the 50S ribosome subunit
  
  

Gene name	obg
Synonyms
Essential	Yes
Product	GTP-binding protein
Function	ribosome assembly, may be required to stimulate activity of the phosphorelay that activates Spo0A
Gene expression levels in SubtiExpress: obg of the phosphorelay that activates Spo0A
Interactions involving this protein in SubtInteract: Obg
MW, pI	47 kDa, 4.859
Gene length, protein length	1284 bp, 428 aa
Immediate neighbours	pheB, spo0B
Sequences	Protein DNA DNA_with_flanks
Genetic context This image was kindly provided by SubtiList
Expression at a glance   PubMed

Categories containing this gene/protein

translation, phosphorelay, essential genes, GTP-binding proteins

The gene

Basic information

• Locus tag: BSU27920

Phenotypes of a mutant

essential PubMed

Database entries

• BsubCyc: BSU27920

• DBTBS entry: [1]

• SubtiList entry: [2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: Binds and hydrolyzes GTP and readily exchanges GDP for GTP

• Protein family: GTP1/OBG family (according to Swiss-Prot) Era/Obg family

• Paralogous protein(s): Era, Obg, YphC, YsxC, RbgA, YqeH, ThdF, YyaF, YnbA

Extended information on the protein

• Kinetic information:

• Domains:

Obg possesses 3 domains: A N-terminal glycine-rich domain (1–158), a GTP binding domain (159–342) and a C-terminal TGS domain (343–428). The TGS domain has no known function, but it is named for three protein families in which it is found, ThrRS, GTPase, and SpoT.

• Modification:

• Cofactor(s):

GDP, GTP and probably ppGpp

• Effectors of protein activity:

• Interactions:
  • RplM-Obg PubMed

Interaction with Rsb proteins.

• Localization:

Database entries

• BsubCyc: BSU27920

• Structure: 1LMZ, 1LNZ

• UniProt: P20964

• KEGG entry: [3]
• E.C. number:

Additional information

The biochemical analysis of bacterial and human Obg proteins combined with the structural observation of the ppGpp nucleotide within the Obg active site suggest a potential role for ppGpp modulation of Obg function in B. subtilis.

Expression and regulation

• Operon: spo0B-obg PubMed

• Expression browser: obg PubMed

• Sigma factor: SigA PubMed

• Regulation:

• Regulatory mechanism:

• Additional information:
  • number of protein molecules per cell (minimal medium with glucose and ammonium): 406 PubMed
  • number of protein molecules per cell (complex medium with amino acids, without glucose): 981 PubMed

Biological materials

• Mutant:

• Expression vector:
  • for expression/ purification from B. subtilis with N-terminal Strep-tag, for SPINE, in pGP380: pGP835, available in Stülke lab
  • for expression/ purification from E. coli with N-terminal His-tag, in pWH844: pGP843, available in Stülke lab

• lacZ fusion:

• GFP fusion:

• two-hybrid system:

• Antibody:

Labs working on this gene/protein

• Bill Haldenwang, San Antonio, USA
• Naotake Ogasawara, Nara, Japan

References

Reviews

Natalie Verstraeten, Maarten Fauvart, Wim Versées, Jan Michiels
The universally conserved prokaryotic GTPases.
Microbiol Mol Biol Rev: 2011, 75(3);507-42, second and third pages of table of contents
[PubMed:21885683] [WorldCat.org] [DOI] (I p)

Robert A Britton
Role of GTPases in bacterial ribosome assembly.
Annu Rev Microbiol: 2009, 63;155-76
[PubMed:19575570] [WorldCat.org] [DOI] (I p)