3AFN

Crystal structure of aldose reductase A1-R complexed with NADP

Summary for 3AFN

• Entry DOI: 10.2210/pdb3afn/pdb
• Related: 3AFM
• Descriptor: Carbonyl reductase, NADP NICOTINAMIDE-ADENINE-DINUCLEOTIDE PHOSPHATE, TERTIARY-BUTYL ALCOHOL, ... (4 entities in total)
• Functional Keywords: alpha/beta/alpha, rossmann-fold, oxidoreductase
• Biological source: Sphingomonas sp.
• Total number of polymer chains: 4
• Total formula weight: 111192.21

Authors

Takase, R.,Ochiai, A.,Mikami, B.,Hashimoto, W.,Murata, K. (deposition date: 2010-03-10, release date: 2010-08-11, Last modification date: 2023-11-01)

Primary citation

Takase, R.,Ochiai, A.,Mikami, B.,Hashimoto, W.,Murata, K.
Molecular identification of unsaturated uronate reductase prerequisite for alginate metabolism in Sphingomonas sp. A1
Biochim.Biophys.Acta, 1804:1925-1936, 2010

PubMed Abstract: In Sphingomonas sp. A1, alginate is degraded by alginate lyases to its constituent monosaccharides, which are nonenzymatically converted to an alpha-keto acid, namely, 4-deoxy-l-erythro-5-hexoseulose uronic acid (DEH). The properties of the DEH-metabolizing enzyme and its gene in strain A1 were characterized. In the presence of alginate, strain A1 cells inducibly produced an NADPH-dependent DEH reductase (A1-R) in their cytoplasm. Molecular cloning of the enzyme gene indicated that A1-R belonged to the short-chain dehydrogenase/reductase superfamily and catalyzed the conversion of DEH to 2-keto-3-deoxy-d-gluconic acid most efficiently at around pH 7.0 and 50 degrees C. Crystal structures of A1-R and its complex with NADP were determined at around 1.6A resolution by X-ray crystallography. The enzyme consists of three layers (alpha/beta/alpha), with a coenzyme-binding Rossmann fold. NADP is surrounded by positively charged residues, and Gly-38 and Arg-39 are crucial for NADP binding. Site-directed mutagenesis studies suggest that Ser-150, Tyr-164, and Lys-168 located around the Rossmann fold constitute the catalytic triad. To our knowledge, this is the first report on molecular cloning and structure determination of a bacterial DEH reductase responsible for alginate metabolism.

PubMed: 20685299
DOI: 10.1016/j.bbapap.2010.05.010

Experimental method

X-RAY DIFFRACTION (1.63 Å)