Obg

• Description: GTP-binding protein involved in initiation of sporulation
  
  

Gene name	obg
Synonyms
Essential	Yes
Product	GTP-binding protein
Function	may be required to stimulate activity of the phosphorelay that activates Spo0A
MW, pI	47 kDa, 4.859
Gene length, protein length	1284 bp, 428 aa
Immediate neighbours	spo0B, pheB
Get the DNA and protein sequences (Barbe et al., 2009)
Genetic context This image was kindly provided by SubtiList

The gene

Basic information

• Coordinates:

Phenotypes of a mutant

essential PubMed

Database entries

• 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:

Interaction with Rsb proteins.

• Localization:

Database entries

• Structure: 1LMZ, 1LNZ

• Swiss prot entry: P20964

• KEGG entry: BSU27920
• 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

• Sigma factor: SigA

• Regulation:

• Regulatory mechanism:

• Additional information:

Biological materials

• Mutant:

• Expression vector: pGP835 (N-terminal Strep-tag, purification from B. subtilis, for SPINE, in pGP380), 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

1. Morimoto T, Loh PC, Hirai T, Asai K, Kobayashi K, Moriya S, Ogasawara N (2002) Six GTP-binding proteins of the Era/Obg family are essential for cell growth in Bacillus subtilis. Microbiology 148: 3539-3552. PubMed
2. Buglino J., Shen V., Hakiman P. & Lima C.D. (2002) Structural and biochemical analysis of the Obg GTP binding protein Structure 10: 1581-1592. PubMed
3. Scott, J.M., Ju, J., Mitchell, T., and Haldenwang, W.G. (2000) The Bacillus subtilis GTP binding protein obg and regulators of the sigma(B) stress response transcription factor cofractionate with ribosomes J. Bacteriol. 182: 2771–2777. PubMed