1bif

[[Image:1bif.gif|left|200px]]<br /><applet load="1bif" size="350" color="white" frame="true" align="right" spinBox="true"

caption="1bif, resolution 2.0&Aring;" />

'''6-PHOSPHOFRUCTO-2-KINASE/FRUCTOSE-2,6-BISPHOSPHATASE BIFUNCTIONAL ENZYME COMPLEXED WITH ATP-G-S AND PHOSPHATE'''<br />

==Overview==

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 A 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 ATPgammaS 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.

 

==About this Structure==

1BIF is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=MG:'>MG</scene>, <scene name='pdbligand=PO4:'>PO4</scene>, <scene name='pdbligand=ATG:'>ATG</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Known structural/functional Sites: <scene name='pdbsite=S1:Walker-A+Motif+(Gxxgxgkt),+Part+Of+Classical+Mononucleot+...'>S1</scene>, <scene name='pdbsite=S2:Walker-B+Motif+(Zzzzd,+Z=Hydrophobic),+Part+Of+Classical+...'>S2</scene> and <scene name='pdbsite=S3:Catalytic+Triad+For+The+Frc-2,6-Bisphosphatase+Reaction'>S3</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1BIF OCA].

 

==Reference==

The crystal structure of the bifunctional enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase reveals distinct domain homologies., Hasemann CA, Istvan ES, Uyeda K, Deisenhofer J, Structure. 1996 Sep 15;4(9):1017-29. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8805587 8805587]

[[Category: Deisenhofer, J.]]

[[Category: Hasemann, C.A.]]