1d4f: Difference between revisions

|PDB= 1d4f |SIZE=350|CAPTION= <scene name='initialview01'>1d4f</scene>, resolution 2.8&Aring;

|SITE=  

|LIGAND= <scene name='pdbligand=ADN:ADENOSINE'>ADN</scene>, <scene name='pdbligand=NAD:NICOTINAMIDE-ADENINE-DINUCLEOTIDE'>NAD</scene>

|ACTIVITY= <span class='plainlinks'>[http://en.wikipedia.org/wiki/Adenosylhomocysteinase Adenosylhomocysteinase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.3.1.1 3.3.1.1] </span>

|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1d4f FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1d4f OCA], [http://www.ebi.ac.uk/pdbsum/1d4f PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1d4f RCSB]</span>

 

 

==Overview==

A site-directed mutagenesis, D244E, of S-adenosylhomocysteine hydrolase (AdoHcyase) changes drastically the nature of the protein, especially the NAD(+) binding affinity. The mutant enzyme contained NADH rather than NAD(+) (Gomi, T., Takata, Y., Date, T., Fujioka, M., Aksamit, R. R., Backlund, P. S., and Cantoni, G. L. (1990) J. Biol. Chem. 265, 16102-16107). In contrast to the site-directed mutagenesis study, the crystal structures of human and rat AdoHcyase recently determined have shown that the carboxyl group of Asp-244 points in a direction opposite to the bound NAD molecule and does not participate in any hydrogen bonds with the NAD molecule. To explain the discrepancy between the mutagenesis study and the x-ray studies, we have determined the crystal structure of the recombinant rat-liver D244E mutant enzyme to 2.8-A resolution. The D244E mutation changes the enzyme structure from the open to the closed conformation by means of a approximately 17 degrees rotation of the individual catalytic domains around the molecular hinge sections. The D244E mutation shifts the catalytic reaction from a reversible to an irreversible fashion. The large affinity difference between NAD(+) and NADH is mainly due to the enzyme conformation, but not to the binding-site geometry; an NAD(+) in the open conformation is readily released from the enzyme, whereas an NADH in the closed conformation is trapped and cannot leave the enzyme. A catalytic mechanism of AdoHcyase has been proposed on the basis of the crystal structures of the wild-type and D244E enzymes.

 

1D4F is a [[Single protein]] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D4F OCA].

 

Effects of site-directed mutagenesis on structure and function of recombinant rat liver S-adenosylhomocysteine hydrolase. Crystal structure of D244E mutant enzyme., Komoto J, Huang Y, Gomi T, Ogawa H, Takata Y, Fujioka M, Takusagawa F, J Biol Chem. 2000 Oct 13;275(41):32147-56. PMID:[http://www.ncbi.nlm.nih.gov/pubmed/10913437 10913437]

[[Category: Adenosylhomocysteinase]]

[[Category: Fujioka, M.]]

[[Category: Gomi, T.]]

[[Category: Huang, Y.]]

[[Category: Komoto, J.]]

[[Category: Ogawa, H.]]

[[Category: Takata, Y.]]

[[Category: Takusagawa, F.]]

[[Category: x-ray crystal structure]]