Xpt

• Description: xanthine phosphoribosyltransferase
  
  

Gene name	xpt
Synonyms
Essential	no
Product	xanthine phosphoribosyltransferase
Function	purine salvage and interconversion
MW, pI	20 kDa, 5.835
Gene length, protein length	582 bp, 194 aa
Immediate neighbours	pbuX, ypwA
Get the DNA and protein sequences (Barbe et al., 2009)
Genetic context This image was kindly provided by SubtiList

The gene

Basic information

• Locus tag: BSU22070

Database entries

• DBTBS entry: [1]

• SubtiList entry: [2]

The protein

Basic information/ Evolution

• Catalyzed reaction/ biological activity: XMP + diphosphate = 5-phospho-alpha-D-ribose 1-diphosphate + xanthine (according to Swiss-Prot)

• Protein family:

• Paralogous protein(s):

Extended information on the protein

• Kinetic information:

• Domains:

• Modification:

• Cofactor(s):

• Effectors of protein activity:

• Interactions:

• Localization: cell membrane (according to Swiss-Prot)

Database entries

• Structure: 1Y0B, 2FXV (complex with GMP), 1Y27 (the riboswitch in complex with guanine)

• Swiss prot entry: P42085

• KEGG entry: [3]

• E.C. number: 2.4.2.22

Additional information

• subject to Clp-dependent proteolysis upon glucose starvation PubMed

Expression and regulation

• Operon: xpt-pbuX PubMed

• Sigma factor:

• Regulation:
  • repressed in the presence of purine nucleotides (PurR) PubMed
  • repressed in the presence of adenine or adenosine (PurR) PubMed
  • induced in the absence of guanine (G-box) PubMed

• Regulatory mechanism:
  • PurR: transcription repression PubMed
  • G-box: transcription termination/ antitermination (riboswitch) PubMed1 PubMed2
  • PurR: transcription repression (molecular inducer: PRPP) PubMed

• Additional information: subject to Clp-dependent proteolysis upon glucose starvation PubMed

Biological materials

• Mutant:

• Expression vector:

• lacZ fusion:

• GFP fusion:

• two-hybrid system:

• Antibody:

References

H H Saxild, K Brunstedt, K I Nielsen, H Jarmer, P Nygaard
Definition of the Bacillus subtilis PurR operator using genetic and bioinformatic tools and expansion of the PurR regulon with glyA, guaC, pbuG, xpt-pbuX, yqhZ-folD, and pbuO.
J Bacteriol: 2001, 183(21);6175-83
[PubMed:11591660] [WorldCat.org] [DOI] (P p)

1. Gerth et al. (2008) Clp-dependent proteolysis down-regulates central metabolic pathways in glucose-starved Bacillus subtilis. J Bacteriol 190:321-331 PubMed
2. Author1, Author2 & Author3 (year) Title Journal volume: page-page. PubMed