3k4c

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Pyranose 2-oxidase H167A/T169G mutantPyranose 2-oxidase H167A/T169G mutant

Structural highlights

3k4c is a 4 chain structure with sequence from Trametes ochracea. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 1.7Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

Q7ZA32_TRAOC

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Pyranose 2-oxidase (P2O) catalyzes the oxidation by O(2) of d-glucose and several aldopyranoses to yield the 2-ketoaldoses and H(2)O(2). Based on crystal structures, in one rotamer conformation, the threonine hydroxyl of Thr(169) forms H-bonds to the flavin-N5/O4 locus, whereas, in a different rotamer, it may interact with either sugar or other parts of the P2O.sugar complex. Transient kinetics of wild-type (WT) and Thr(169) --> S/N/G/A replacement variants show that D-Glc binds to T169S, T169N, and WT with the same K(d) (45-47 mm), and the hydride transfer rate constants (k(red)) are similar (15.3-9.7 s(-1) at 4 degrees C). k(red) of T169G with D-glucose (0.7 s(-1), 4 degrees C) is significantly less than that of WT but not as severely affected as in T169A (k(red) of 0.03 s(-1) at 25 degrees C). Transient kinetics of WT and mutants using d-galactose show that P2O binds d-galactose with a one-step binding process, different from binding of d-glucose. In T169S, T169N, and T169G, the overall turnover with d-Gal is faster than that of WT due to an increase of k(red). In the crystal structure of T169S, Ser(169) O gamma assumes a position identical to that of O gamma 1 in Thr(169); in T169G, solvent molecules may be able to rescue H-bonding. Our data suggest that a competent reductive half-reaction requires a side chain at position 169 that is able to form an H-bond within the ES complex. During the oxidative half-reaction, all mutants failed to stabilize a C4a-hydroperoxyflavin intermediate, thus suggesting that the precise position and geometry of the Thr(169) side chain are required for intermediate stabilization.

A conserved active-site threonine is important for both sugar and flavin oxidations of pyranose 2-oxidase.,Pitsawong W, Sucharitakul J, Prongjit M, Tan TC, Spadiut O, Haltrich D, Divne C, Chaiyen P J Biol Chem. 2010 Mar 26;285(13):9697-705. Epub 2010 Jan 20. PMID:20089849[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Pitsawong W, Sucharitakul J, Prongjit M, Tan TC, Spadiut O, Haltrich D, Divne C, Chaiyen P. A conserved active-site threonine is important for both sugar and flavin oxidations of pyranose 2-oxidase. J Biol Chem. 2010 Mar 26;285(13):9697-705. Epub 2010 Jan 20. PMID:20089849 doi:10.1074/jbc.M109.073247

3k4c, resolution 1.70Å

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