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Search The CSA
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Catalytic Site Atlas

CSA LITERATURE entry for 1p5d

E.C. namephosphomannomutase
SpeciesPseudomonas aeruginosa (Bacteria)
E.C. Number (IntEnz) 5.4.2.8
CSA Homologues of 1p5dThere are 12 Homologs
CSA Entries With UniProtID P26276
CSA Entries With EC Number 5.4.2.8
PDBe Entry 1p5d
PDBSum Entry 1p5d
MACiE Entry M0194

Literature Report

IntroductionPhosphomannomutase or phosphoglucomutase (PMM/PGM) from Pseudomonas aeruginosa can catalyse the same reaction in two different substrates. It catalyses the transfer of a phosphoryl group from the 6 position to the 1 position in either mannose 6-P or glucose 6-P. PMM/PGM activity is required for the biosynthesis of lipopolysaccharides in Pseudomonas aeruginosa.
Mechansim1. Residues Arg 20, His 109, Lys 118, Arg247 and His 329 along with cofactor Mg2+ form a positive electrostatic field. This decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. 2. The substrate O atom then nucleophilically attacks the phosphorus of Sep 108, which acts as an electrophile, and the Serine O-P bond is broken. 3. The above residues (and co-factor) then act to stabilise the Ser 108 alkoxide. 4. Rotation of the substrate occurs, arranging the C6 phospho group toward Ser 108. 5. Ser 108 then nucleophilically attacks the C6 phosphorus atom, breaking the P-O bond of the substrate. 6. The substrate is then re-protonated to form the 1-P product.
Reaction

Catalytic Sites for 1p5d

Annotated By Reference To The Literature - Site 1 (Perform Site Search)
ResidueChainNumberUniProtKB NumberFunctional PartFunctionTargetDescription
HisX109109macie:sideChainHelps form a positive electrostatic field which decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. Also helps stabilise the Ser 108 alkoxide.
LysX118118macie:sideChainHelps form a positive electrostatic field which decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. Also helps stabilise the Ser 108 alkoxide.
HisX329329macie:sideChainHelps form a positive electrostatic field which decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. Also helps stabilise the Ser 108 alkoxide.
ArgX247247macie:sideChainHelps form a positive electrostatic field which decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. Also helps stabilise the Ser 108 alkoxide.
ArgX2020macie:sideChainHelps form a positive electrostatic field which decreases the pKa of the proton on the hydroxyl of C1 to such an extent as to cause spontaneous ionization. Also helps stabilise the Ser 108 alkoxide.
SepX108108macie:ptmSep 108 donates a phospho group to the C1 position, then removes a phospho group from the C6 position of the substrate.

Literature References

Notes:
Naught LE
Roles of active site residues in Pseudomonas aeruginosa phosphomannomutase/phosphoglucomutase.
Biochemistry 2003 42 9946-9951
PubMed: 12924943
Regni C
Structural basis of diverse substrate recognition by the enzyme PMM/PGM from P. aeruginosa.
Structure 2004 12 55-63
PubMed: 14725765
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