TY - JOUR
T1 - The crystal structure of the bifunctional enzyme 6-phosphofructo-2- kinase/fructose-2,6-bisphosphatase reveals distinct domain homologies
AU - Hasemann, Charles A.
AU - Istvan, Eva S.
AU - Uyeda, Kosaku
AU - Deisenhofer, Johann
N1 - Funding Information:
We would like to thank Cu Nguyen for excellent technical assistance in the preparation and crystallization of the enzyme, and Ravichandran Kurumbail, whose enthusiasm for this project kept it alive in the early stages. This work was supported by The Welch Foundation (CH), Howard Hughes Medical Institute (JD), the Veterans Administration (KU), and the NIH (DK16194, KU).
PY - 1996/9/15
Y1 - 1996/9/15
N2 - Background: Glucose homeostasis is maintained by the processes of glycolysis and gluconeogenesis. The importance of these pathways is demonstrated by the severe and life threatening effects observed in various forms of diabetes. The bifunctional enzyme 6-phosphofructo-2- kinase/fructose-2,6-bisphosphatase catalyzes both the synthesis and degradation of fructose-2,6-bisphosphate, a potent regulator of glycolysis. Thus this bifunctional enzyme plays an indirect yet key role in the regulation of glucose metabolism. Results: We have determined the 2.0 Å crystal structure of the rat testis isozyme of this bifunctional enzyme. The enzyme is a homodimer of 55 kDa subunits arranged in a head-to-head fashion, with each monomer consisting of independent kinase and phosphatase domains. The location of ATPγS and inorganic phosphate in the kinase and phosphatase domains, respectively, allow us to locate and describe the active sites of both domains. Conclusions: The kinase domain is clearly related to the superfamily of mononucleotide binding proteins, with a particularly close relationship to the adenylate kinases and the nucleotide-binding portion of the G proteins. This is in disagreement with the broad speculation that this domain would resemble phosphofructokinase. The phosphatase domain is structurally related to a family of proteins which includes the cofactor independent phosphoglycerate mutases and acid phosphatases.
AB - Background: Glucose homeostasis is maintained by the processes of glycolysis and gluconeogenesis. The importance of these pathways is demonstrated by the severe and life threatening effects observed in various forms of diabetes. The bifunctional enzyme 6-phosphofructo-2- kinase/fructose-2,6-bisphosphatase catalyzes both the synthesis and degradation of fructose-2,6-bisphosphate, a potent regulator of glycolysis. Thus this bifunctional enzyme plays an indirect yet key role in the regulation of glucose metabolism. Results: We have determined the 2.0 Å crystal structure of the rat testis isozyme of this bifunctional enzyme. The enzyme is a homodimer of 55 kDa subunits arranged in a head-to-head fashion, with each monomer consisting of independent kinase and phosphatase domains. The location of ATPγS and inorganic phosphate in the kinase and phosphatase domains, respectively, allow us to locate and describe the active sites of both domains. Conclusions: The kinase domain is clearly related to the superfamily of mononucleotide binding proteins, with a particularly close relationship to the adenylate kinases and the nucleotide-binding portion of the G proteins. This is in disagreement with the broad speculation that this domain would resemble phosphofructokinase. The phosphatase domain is structurally related to a family of proteins which includes the cofactor independent phosphoglycerate mutases and acid phosphatases.
KW - X-ray crystallography
KW - bifunctional enzyme
KW - phosphoric monoester hydrolase
KW - phosphotransferase
KW - protein structure
UR - http://www.scopus.com/inward/record.url?scp=0030587517&partnerID=8YFLogxK
U2 - 10.1016/S0969-2126(96)00109-8
DO - 10.1016/S0969-2126(96)00109-8
M3 - Article
C2 - 8805587
AN - SCOPUS:0030587517
VL - 4
SP - 1017
EP - 1029
JO - Structure
JF - Structure
SN - 0969-2126
IS - 9
ER -