|Protein name||Lactose-specific phosphotransferase enzyme IIA component|
|Synonyms||EC 2.7.1.-PTS system lactose-specific EIIA componentEIIA-LacEIII-Lac|
|Activity||Protein EIIA N(pi)-phospho-L-histidine + protein EIIB = protein EIIA + protein EIIB N(pi)-phospho-L- histidine/cysteine.|
|Cofactor||Binds 1 magnesium ion per trimer.|
|Compound||Protein N(pi)-phospho-L-histidine||Protein cysteine||Protein histidine||Protein S-phosphoryl-cysteine|
|Type||aromatic ring (with nitrogen atoms),peptide/protein,phosphate group/phosphate ion||peptide/protein,sulfhydryl group||aromatic ring (with nitrogen atoms),peptide/protein||peptide/protein,phosphate group/phosphate ion,sulfide group|
|References for Catalytic Mechanism|
|References||Sections||No. of steps in catalysis|
|Authors||Sliz P, Engelmann R, Hengstenberg W, Pai EF|
|Title||The structure of enzyme IIAlactose from Lactococcus lactis reveals a new fold and points to possible interactions of a multicomponent system.|
|This Enzyme is involved in PTS system, to which the other phosphoryl transferases (S00297, D00527, D00525, S00283, S00420 in EzCatDB) also belong. Many of such enzymes have got the same E.C. number (18.104.22.168). This enzyme also had the same E.C. number previously, which was changed to 2.7.1.-.|
Moreover, this enzyme seems to transfer the phosphoryl group from His residue of Phosphocarrier protein HPr (Swiss-prot;Q9CJ83) to Cys residue of the PTS system lactose-specific EIIB component (Swiss-prot;P23531), which is homologous to the counterpart enzyme from E. coli (D00525 in EzCatDB).
His78 is the active site, which is phosphorylated by phosphorylcarrier protein, HPr. The NE atom of His78 must be deprotonated at physiolosical pH . And then, this enzyme phosphorylates IIBlactose domain in PTS system (cf. D00525).