Pyridoxal kinase catalyzes the phosphorylation of pyridoxal (PL) to pyridoxal 5'-phosphate (PLP). A D235A variant shows 7-fold and 15-fold decreases in substrate affinity and activity, respectively. A D235N variant shows similar to 2-fold decrease in both PL affinity and activity. The crystal structure of D235A (2.5 angstrom) shows bound ATP, PL and PLP, while D235N (2.3 angstrom) shows bound ATP and sulfate. These results document the role of Asp235 in PL kinase activity. The observation that the active site of PL kinase can accommodate both ATP and PLP suggests that formation of a ternary Enz-PLP-ATP complex could occur in the wild-type enzyme, consistent with severe MgATP substrate inhibition of PL kinase in the presence of PLP. (C) 2009 Elsevier Inc. All rights reserved.
Kinetic and structural studies of the role of the active site residue Asp235 of human pyridoxal kinase / K., Gandhi Amit; Mohini S., Ghatge; Faik N., Musayev; Aaron, Sease; O., Aboagye Samuel; DI SALVO, Martino Luigi; Verne, Schirch; K., Safo Martin. - In: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - ISSN 0006-291X. - STAMPA. - 381:1(2009), pp. 12-15. [10.1016/j.bbrc.2009.01.170]
Kinetic and structural studies of the role of the active site residue Asp235 of human pyridoxal kinase
DI SALVO, Martino Luigi;
2009
Abstract
Pyridoxal kinase catalyzes the phosphorylation of pyridoxal (PL) to pyridoxal 5'-phosphate (PLP). A D235A variant shows 7-fold and 15-fold decreases in substrate affinity and activity, respectively. A D235N variant shows similar to 2-fold decrease in both PL affinity and activity. The crystal structure of D235A (2.5 angstrom) shows bound ATP, PL and PLP, while D235N (2.3 angstrom) shows bound ATP and sulfate. These results document the role of Asp235 in PL kinase activity. The observation that the active site of PL kinase can accommodate both ATP and PLP suggests that formation of a ternary Enz-PLP-ATP complex could occur in the wild-type enzyme, consistent with severe MgATP substrate inhibition of PL kinase in the presence of PLP. (C) 2009 Elsevier Inc. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
