1dr3: Difference between revisions
No edit summary |
No edit summary |
||
| Line 1: | Line 1: | ||
[[Image:1dr3.gif|left|200px]] | [[Image:1dr3.gif|left|200px]] | ||
<!-- | |||
The line below this paragraph, containing "STRUCTURE_1dr3", creates the "Structure Box" on the page. | |||
You may change the PDB parameter (which sets the PDB file loaded into the applet) | |||
or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |||
or leave the SCENE parameter empty for the default display. | |||
| | --> | ||
| | {{STRUCTURE_1dr3| PDB=1dr3 | SCENE= }} | ||
}} | |||
'''2.3 ANGSTROMS CRYSTAL STRUCTURE OF CHICKEN LIVER DIHYDROFOLATE REDUCTASE COMPLEXED WITH THIONADP+ AND BIOPTERIN''' | '''2.3 ANGSTROMS CRYSTAL STRUCTURE OF CHICKEN LIVER DIHYDROFOLATE REDUCTASE COMPLEXED WITH THIONADP+ AND BIOPTERIN''' | ||
| Line 31: | Line 28: | ||
[[Category: Mctigue, M A.]] | [[Category: Mctigue, M A.]] | ||
[[Category: Xuong, N H.]] | [[Category: Xuong, N H.]] | ||
[[Category: | [[Category: Oxidoreductase]] | ||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 14:10:47 2008'' | |||
''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | |||
Revision as of 14:10, 2 May 2008
2.3 ANGSTROMS CRYSTAL STRUCTURE OF CHICKEN LIVER DIHYDROFOLATE REDUCTASE COMPLEXED WITH THIONADP+ AND BIOPTERIN
OverviewOverview
The role of the 3'-carboxamide substituent of NADPH in the reduction of pteridine substrates as catalyzed by dihydrofolate reductase (EC 1.5.1.3, DHFR) has been investigated by determining crystal structures at 2.3 A of chicken liver DHFR in a binary complex with oxidized thionicotinamide adenine dinucleotide (thioNADP+) and in a ternary complex with thioNADP+ and biopterin. These structures are isomorphous with those previously reported for chicken liver DHFR [Volz, K.W., Matthews, D.A., Alden, R.A., Freer, S. T., Hansch, C., Kaufman, B. T., & Kraut, J. (1982) J. Biol. Chem. 257, 2528-2536]. ThioNADPH, which has a 3'-carbothioamide substituent in place of a 3'-carboxamide, functions very poorly as a coenzyme for DHFR [Williams, T. J., Lee, T. K., & Dunlap, R. B. (1977) Arch, Biochem. Biophys. 181, 569-579; Stone, S. R., Mark, A., & Morrison, J. F. (1984) Biochemistry 23, 4340-4346]. Comparisons show that, while NADP+ and NADPH bind to DHFR with the pyridine ring and 3'-carboxamide coplanar, the thioamide group is twisted by 23 degrees from the pyridine plane in both the binary and ternary complexes. This twist appears to be due to steric conflict between the thioamide sulfur atom and both the pyridine ring at C4 and the adjacent protein backbone at Ala-9. It results in an unfavorably close contact between the sulfur and the biopterin pteridine ring (0.9 A less than the van der Waals separation) which, on the basis of the refined structure, greatly destabilizes the binding of biopterin.(ABSTRACT TRUNCATED AT 250 WORDS)
About this StructureAbout this Structure
1DR3 is a Single protein structure of sequence from Gallus gallus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structures of chicken liver dihydrofolate reductase: binary thioNADP+ and ternary thioNADP+.biopterin complexes., McTigue MA, Davies JF 2nd, Kaufman BT, Kraut J, Biochemistry. 1993 Jul 13;32(27):6855-62. PMID:8334118 Page seeded by OCA on Fri May 2 14:10:47 2008