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Enzyme Architecture: A Startling Role for Asn270 in Glycerol 3-Phosphate Dehydrogenase-Catalyzed Hydride Transfer.
- Source :
-
Biochemistry [Biochemistry] 2016 Mar 15; Vol. 55 (10), pp. 1429-32. Date of Electronic Publication: 2016 Mar 03. - Publication Year :
- 2016
-
Abstract
- The side chains of R269 and N270 interact with the phosphodianion of dihydroxyacetone phosphate (DHAP) bound to glycerol 3-phosphate dehydrogenase (GPDH). The R269A, N270A, and R269A/N270A mutations of GPDH result in 9.1, 5.6, and 11.5 kcal/mol destabilization, respectively, of the transition state for GPDH-catalyzed reduction of DHAP by the reduced form of nicotinamide adenine dinucleotide. The N270A mutation results in a 7.7 kcal/mol decrease in the intrinsic phosphodianion binding energy, which is larger than the 5.6 kcal/mol effect of the mutation on the stability of the transition state for reduction of DHAP; a 2.2 kcal/mol stabilization of the transition state for unactivated hydride transfer to the truncated substrate glycolaldehyde (GA); and a change in the effect of phosphite dianion on GPDH-catalyzed reduction of GA, from strongly activating to inhibiting. The N270A mutation breaks the network of hydrogen bonding side chains, Asn270, Thr264, Asn205, Lys204, Asp260, and Lys120, which connect the dianion activation and catalytic sites of GPDH. We propose that this disruption dramatically alters the performance of GPDH at these sites.
- Subjects :
- Boranes metabolism
Catalysis
Crystallography, X-Ray
Glycerolphosphate Dehydrogenase genetics
Humans
Liver enzymology
Protein Structure, Secondary
Protein Structure, Tertiary
Asparagine physiology
Catalytic Domain physiology
Glycerolphosphate Dehydrogenase chemistry
Glycerolphosphate Dehydrogenase metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1520-4995
- Volume :
- 55
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Biochemistry
- Publication Type :
- Academic Journal
- Accession number :
- 26926520
- Full Text :
- https://doi.org/10.1021/acs.biochem.6b00116