A novel NAD-binding protein revealed by the crystal structure of 2,3-diketo-L-gulonate reductase (YiaK)
| Autor: | Kaushal Kulkarni, Thomas Acton, Rong Xiao, Gaetano T. Montelione, Farhad Forouhar, Insun Lee, Liang Tong, Jordi Benach |
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| Rok vydání: | 2004 |
| Předmět: |
Models
Molecular Stereochemistry Protein Conformation Molecular Sequence Data Electrons Reductase Crystallography X-Ray Biochemistry Cofactor Oxidoreductase Catalytic Domain Escherichia coli Enzyme kinetics Amino Acid Sequence Molecular Biology Tartrates chemistry.chemical_classification Binding Sites biology Sequence Homology Amino Acid Escherichia coli Proteins Active site Sugar Acids Cell Biology NAD Protein Structure Tertiary NAD binding Kinetics Enzyme chemistry Models Chemical biology.protein NAD+ kinase Dimerization Protein Binding Sugar Alcohol Dehydrogenases |
| Zdroj: | The Journal of biological chemistry. 279(13) |
| ISSN: | 0021-9258 |
| Popis: | Escherichia coli YiaK catalyzes the reduction of 2,3-diketo-l-gulonate in the presence of NADH. It belongs to a large family of oxidoreductases that is conserved in archaea, bacteria, and eukaryotes but shows no sequence homology to other proteins. We report here the crystal structures at up to 2.0-A resolution of YiaK alone and in complex with NAD-tartrate. YiaK has a new polypeptide backbone fold and a novel mode of recognizing the NAD cofactor. In addition, NAD is bound in an unusual conformation, at the interface of a dimer of the enzyme. The crystallographic analysis unexpectedly revealed the binding of tartrate in the active site. Enzyme kinetics studies confirm that tartrate and the related d-malate are inhibitors of YiaK. In contrast to most other enzymes where substrate binding produces a more closed conformation, the binding of NAD-tartrate to YiaK produces a more open active site. The free enzyme conformation is incompatible with NAD binding. His44 is likely the catalytic residue of the enzyme. |
| Databáze: | OpenAIRE |
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