Publication Abstract from PubMed
Carbamate kinase catalyzes the reversible conversion of carbamoyl phosphate and ADP to ATP and ammonium carbamate, which is hydrolyzed to ammonia and carbonate. The three-dimensional structure of carbamate kinase from the human parasite Giardia lamblia (glCK) has been determined at 3 A resolution. The crystals belonged to the monoclinic space group P2(1), with unit-cell parameters a = 69.77, b = 85.41, c = 102.1 A, beta = 106.8 degrees . The structure was refined to a final R factor of 0.227. The essentiality of glCK together with its absence in humans makes the enzyme an attractive candidate for anti-Giardia drug development. Steady-state kinetic rate constants have been determined. The k(cat) for ATP formation is 319 +/- 9 s(-1). The K(m) values for carbamoyl phosphate and ADP are 85 +/- 6 and 70 +/- 5 microM, respectively. The structure suggests that three invariant lysine residues (Lys131, Lys216 and Lys278) may be involved in the binding of substrates and phosphoryl transfer. The structure of glCK reveals that a glycerol molecule binds in the likely carbamoyl phosphate-binding site.
X-ray structure and characterization of carbamate kinase from the human parasite Giardia lamblia.,Galkin A, Kulakova L, Wu R, Nash TE, Dunaway-Mariano D, Herzberg O Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Apr 1;66(Pt 4):386-90., Epub 2010 Mar 26. PMID:20383005[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
