2OQY

The crystal structure of muconate cycloisomerase from Oceanobacillus iheyensis

2OQY の概要

• エントリーDOI: 10.2210/pdb2oqy/pdb
• 分子名称: Muconate cycloisomerase, MAGNESIUM ION (3 entities in total)
• 機能のキーワード: enolase superfamily, structural genomics, target 9375a, nysgrc, psi-2, protein structure initiative, new york sgx research center for structural genomics, nysgxrc, isomerase
• 由来する生物種: Oceanobacillus iheyensis
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 355615.82

構造登録者

Fedorov, A.A.,Toro, R.,Fedorov, E.V.,Bonanno, J.,Sauder, J.M.,Burley, S.K.,Gerlt, J.A.,Almo, S.C.,New York SGX Research Center for Structural Genomics (NYSGXRC) (登録日: 2007-02-01, 公開日: 2007-03-06, 最終更新日: 2023-12-27)

主引用文献

Rakus, J.F.,Kalyanaraman, C.,Fedorov, A.A.,Fedorov, E.V.,Mills-Groninger, F.P.,Toro, R.,Bonanno, J.,Bain, K.,Sauder, J.M.,Burley, S.K.,Almo, S.C.,Jacobson, M.P.,Gerlt, J.A.
Computation-facilitated assignment of the function in the enolase superfamily: a regiochemically distinct galactarate dehydratase from Oceanobacillus iheyensis .
Biochemistry, 48:11546-11558, 2009

PubMed Abstract: The structure of an uncharacterized member of the enolase superfamily from Oceanobacillus iheyensis (GI 23100298, IMG locus tag Ob2843, PDB entry 2OQY ) was determined by the New York SGX Research Center for Structural Genomics (NYSGXRC). The structure contained two Mg(2+) ions located 10.4 A from one another, with one located in the canonical position in the (beta/alpha)(7)beta-barrel domain (although the ligand at the end of the fifth beta-strand is His, unprecedented in structurally characterized members of the superfamily); the second is located in a novel site within the capping domain. In silico docking of a library of mono- and diacid sugars to the active site predicted a diacid sugar as a likely substrate. Activity screening of a physical library of acid sugars identified galactarate as the substrate (k(cat) = 6.8 s(-1), K(M) = 620 microM, k(cat)/K(M) = 1.1 x 10(4) M(-1) s(-1)), allowing functional assignment of Ob2843 as galactarate dehydratase (GalrD-II). The structure of a complex of the catalytically impaired Y90F mutant with Mg(2+) and galactarate allowed identification of a Tyr 164-Arg 162 dyad as the base that initiates the reaction by abstraction of the alpha-proton and Tyr 90 as the acid that facilitates departure of the beta-OH leaving group. The enzyme product is 2-keto-d-threo-4,5-dihydroxyadipate, the enantiomer of the product obtained in the GalrD reaction catalyzed by a previously characterized bifunctional l-talarate/galactarate dehydratase (TalrD/GalrD). On the basis of the different active site structures and different regiochemistries, we recognize that these functions represent an example of apparent, not actual, convergent evolution of function. The structure of GalrD-II and its active site architecture allow identification of the seventh functionally and structurally characterized subgroup in the enolase superfamily. This study provides an additional example in which an integrated sequence- and structure-based strategy employing computational approaches is a viable approach for directing functional assignment of unknown enzymes discovered in genome projects.

PubMed: 19883118
DOI: 10.1021/bi901731c

実験手法

X-RAY DIFFRACTION (2 Å)