Publications

• Urkinase: structure of acetate kinase, a member of the ASKHA superfamily of phosphotransferases.

  Buss K.A., Cooper D.R., Ingram-Smith C., Ferry J.G., Sanders D.A., Hasson M.S.

  Acetate kinase, an enzyme widely distributed in the Bacteria and Archaea domains, catalyzes the phosphorylation of acetate. We have determined the three-dimensional structure of Methanosarcina thermophila acetate kinase bound to ADP through crystallography. As we previously predicted, acetate kina ... >> More

  Acetate kinase, an enzyme widely distributed in the Bacteria and Archaea domains, catalyzes the phosphorylation of acetate. We have determined the three-dimensional structure of Methanosarcina thermophila acetate kinase bound to ADP through crystallography. As we previously predicted, acetate kinase contains a core fold that is topologically identical to that of the ADP-binding domains of glycerol kinase, hexokinase, the 70-kDa heat shock cognate (Hsc70), and actin. Numerous charged active-site residues are conserved within acetate kinases, but few are conserved within the phosphotransferase superfamily. The identity of the points of insertion of polypeptide segments into the core fold of the superfamily members indicates that the insertions existed in the common ancestor of the phosphotransferases. Another remarkable shared feature is the unusual, epsilon conformation of the residue that directly precedes a conserved glycine residue (Gly-331 in acetate kinase) that binds the alpha-phosphate of ADP. Structural, biochemical, and geochemical considerations indicate that an acetate kinase may be the ancestral enzyme of the ASKHA (acetate and sugar kinases/Hsc70/actin) superfamily of phosphotransferases. << Less

  J. Bacteriol. 183:680-686(2001) [PubMed] [EuropePMC]

• Cloning, expression, and characterization of acetate kinase from Lactobacillus sanfranciscensis.

  Knorr R., Ehrmann M.A., Vogel R.F.

  In the metabolism of Lactobacillus sanfranciscensis, the acetate kinase (AK) is a key enzyme and responsible for dephosphorylation of acetyl phosphate with the concomitant production of acetate and ATP. The L. sanfranciscensis ack gene was identified by PCR methods. It encodes a 397 amino acid pro ... >> More

  In the metabolism of Lactobacillus sanfranciscensis, the acetate kinase (AK) is a key enzyme and responsible for dephosphorylation of acetyl phosphate with the concomitant production of acetate and ATP. The L. sanfranciscensis ack gene was identified by PCR methods. It encodes a 397 amino acid protein sharing 56% similarity with Bacillus subtilis AK. Whereas cotranscription of ack and pta (phosphotransacetylase) is reported in previously characterised organisms, the L. sanfranciscensis ack gene is not located in direct neighbourhood to the encoding gene. AK was heterologously expressed in E. coli and characterised by its v(max) and Km values and by the dependence of enzyme activity on temperature and pH. Based on this data the in vivo role of the enzyme is discussed. << Less

  Microbiol Res 156:267-277(2001) [PubMed] [EuropePMC]

• Structural and kinetic analyses of arginine residues in the active site of the acetate kinase from Methanosarcina thermophila.

  Gorrell A., Lawrence S.H., Ferry J.G.

  Acetate kinase catalyzes transfer of the gamma-phosphate of ATP to acetate. The only crystal structure reported for acetate kinase is the homodimeric enzyme from Methanosarcina thermophila containing ADP and sulfate in the active site (Buss, K. A., Cooper, D. C., Ingram-Smith, C., Ferry, J. G., Sa ... >> More

  Acetate kinase catalyzes transfer of the gamma-phosphate of ATP to acetate. The only crystal structure reported for acetate kinase is the homodimeric enzyme from Methanosarcina thermophila containing ADP and sulfate in the active site (Buss, K. A., Cooper, D. C., Ingram-Smith, C., Ferry, J. G., Sanders, D. A., and Hasson, M. S. (2001) J. Bacteriol. 193, 680-686). Here we report two new crystal structure of the M. thermophila enzyme in the presence of substrate and transition state analogs. The enzyme co-crystallized with the ATP analog adenosine 5'-[gamma-thio]triphosphate contained AMP adjacent to thiopyrophosphate in the active site cleft of monomer B. The enzyme co-crystallized with ADP, acetate, Al(3+), and F(-) contained a linear array of ADP-AlF(3)-acetate in the active site cleft of monomer B. Together, the structures clarify the substrate binding sites and support a direct in-line transfer mechanism in which AlF(3) mimics the meta-phosphate transition state. Monomers A of both structures contained ADP and sulfate, and the active site clefts were closed less than in monomers B, suggesting that domain movement contributes to catalysis. The finding that His(180) was in close proximity to AlF(3) is consistent with a role for stabilization of the meta-phosphate that is in agreement with a previous report indicating that this residue is essential for catalysis. Residue Arg(241) was also found adjacent to AlF(3), consistent with a role for stabilization of the transition state. Kinetic analyses of Arg(241) and Arg(91) replacement variants indicated that these residues are essential for catalysis and also indicated a role in binding acetate. << Less

  J. Biol. Chem. 280:10731-10742(2005) [PubMed] [EuropePMC]