MetaCyc Enzyme: glutamate-tyrosine ligase

Gene: pqqE Accession Number: G-11753 (MetaCyc)

Species: Klebsiella pneumoniae

PqqE is a member of the radical SAM proteins, and is thus proposed to catalyze the C-C bond formation between the L-glutamate and L-tyrosine residues of the pyrroloquinoline quinone biosynthesis protein A. According to the model, the enzyme, using its 4Fe-4S center, produces a radical SAM molecule, which abstracts a hydrogen from the L-tyrosine residue, creating a tyrosine radical which reacts with the C9 carbon of the L-glutamate, leading to cyclization [Puehringer08].

When the full pqq operon was cloned and expressed in Escherichia coli, the host organism was able to produce pyrroloquinoline quinone. Omission of the pqqE gene abolished PQQ production [Velterop95].

Gene Citations: [Meulenberg92]

Molecular Weight of Polypeptide: 42.914 kD (from nucleotide sequence), 40.0 kD (experimental) [Magnusson04 ]

pI: 5.7 [Puehringer08]

Unification Links: Protein Model Portal:P27507 , UniProt:P27507

Relationship Links: Entrez-Nucleotide:PART-OF:X58778 , InterPro:IN-FAMILY:IPR000385 , InterPro:IN-FAMILY:IPR006638 , InterPro:IN-FAMILY:IPR007197 , InterPro:IN-FAMILY:IPR011843 , InterPro:IN-FAMILY:IPR013785 , InterPro:IN-FAMILY:IPR017200 , InterPro:IN-FAMILY:IPR023885 , Pfam:IN-FAMILY:PF04055 , Pfam:IN-FAMILY:PF13186 , Prosite:IN-FAMILY:PS01305 , Smart:IN-FAMILY:SM00729

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 20-Jan-2010 by Caspi R , SRI International

Enzymatic reaction of: glutamate-tyrosine ligase

a PqqA peptide + an oxidized unknown electron acceptor <=> a PqqA peptide with linked Glu-Tyr residues + an reduced unknown electron acceptor

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction in which it was curated.

The reaction is favored in the direction shown.

In Pathways: pyrroloquinoline quinone biosynthesis

Cofactors or Prosthetic Groups: a [4Fe-4S] iron-sulfur cluster [Puehringer08]


Magnusson04: Magnusson OT, Toyama H, Saeki M, Rojas A, Reed JC, Liddington RC, Klinman JP, Schwarzenbacher R (2004). "Quinone biogenesis: Structure and mechanism of PqqC, the final catalyst in the production of pyrroloquinoline quinone." Proc Natl Acad Sci U S A 101(21);7913-8. PMID: 15148379

Meulenberg92: Meulenberg JJ, Sellink E, Riegman NH, Postma PW (1992). "Nucleotide sequence and structure of the Klebsiella pneumoniae pqq operon." Mol Gen Genet 232(2);284-94. PMID: 1313537

Puehringer08: Puehringer S, Metlitzky M, Schwarzenbacher R (2008). "The pyrroloquinoline quinone biosynthesis pathway revisited: a structural approach." BMC Biochem 9;8. PMID: 18371220

Velterop95: Velterop JS, Sellink E, Meulenberg JJ, David S, Bulder I, Postma PW (1995). "Synthesis of pyrroloquinoline quinone in vivo and in vitro and detection of an intermediate in the biosynthetic pathway." J Bacteriol 177(17);5088-98. PMID: 7665488

Report Errors or Provide Feedback
Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
Page generated by SRI International Pathway Tools version 19.0 on Sat Oct 10, 2015, BIOCYC14A.