Xpt

• Description: xanthine phosphoribosyltransferase
  
  

Gene name	xpt
Synonyms
Essential	no
Product	xanthine phosphoribosyltransferase
Function	purine salvage and interconversion
Metabolic function and regulation of this protein in SubtiPathways: Purine salvage, Nucleotides (regulation)
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]

Categories containing this gene/protein

biosynthesis/ acquisition of nucleotides, membrane proteins

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)

• UniProt: 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: SigA PubMed

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

• Regulatory mechanism:
  • G-box: transcription termination/ antitermination (riboswitch) PubMed
  • 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: pGP430 (in pAC7), available in Stülke lab

• GFP fusion:

• two-hybrid system:

• Antibody: