4XF4

Cysteine dioxygenase at pH 8.0 in complex with homocysteine

Summary for 4XF4

• Entry DOI: 10.2210/pdb4xf4/pdb
• Related: 4EXT 4IEO 4IEP 4IEQ 4IER 4IES 4IET 4IEU 4IEV 4IEW 4IEX 4IEY 4IEZ 4JTN 4JTO 4KWK 4KWL 4PIX 4PIY 4PIZ 4PJY 4XEZ 4XF0 4XF1 4XF3
• Descriptor: Cysteine dioxygenase type 1, FE (III) ION, 2-AMINO-4-MERCAPTO-BUTYRIC ACID, ... (4 entities in total)
• Functional Keywords: cupin fold, cysteine to cysteine sulfinic acid catalysis, thiol dioxygenase, oxidoreductase
• Biological source: Rattus norvegicus (Rat)
• Total number of polymer chains: 1
• Total formula weight: 23249.92

Authors

Driggers, C.M.,Karplus, P.A. (deposition date: 2014-12-26, release date: 2016-03-16, Last modification date: 2024-11-20)

Primary citation

Driggers, C.M.,Kean, K.M.,Hirschberger, L.L.,Cooley, R.B.,Stipanuk, M.H.,Karplus, P.A.
Structure-Based Insights into the Role of the Cys-Tyr Crosslink and Inhibitor Recognition by Mammalian Cysteine Dioxygenase.
J. Mol. Biol., 428:3999-4012, 2016

PubMed Abstract: In mammals, the non-heme iron enzyme cysteine dioxygenase (CDO) helps regulate Cys levels through converting Cys to Cys sulfinic acid. Its activity is in part modulated by the formation of a Cys93-Tyr157 crosslink that increases its catalytic efficiency over 10-fold. Here, 21 high-resolution mammalian CDO structures are used to gain insight into how the Cys-Tyr crosslink promotes activity and how select competitive inhibitors bind. Crystal structures of crosslink-deficient C93A and Y157F variants reveal similar ~1.0-Å shifts in the side chain of residue 157, and both variant structures have a new chloride ion coordinating the active site iron. Cys binding is also different from wild-type CDO, and no Cys-persulfenate forms in the C93A or Y157F active sites at pH6.2 or 8.0. We conclude that the crosslink enhances activity by positioning the Tyr157 hydroxyl to enable proper Cys binding, proper oxygen binding, and optimal chemistry. In addition, structures are presented for homocysteine (Hcy), D-Cys, thiosulfate, and azide bound as competitive inhibitors. The observed binding modes of Hcy and D-Cys clarify why they are not substrates, and the binding of azide shows that in contrast to what has been proposed, it does not bind in these crystals as a superoxide mimic.

PubMed: 27477048
DOI: 10.1016/j.jmb.2016.07.012

Experimental method

X-RAY DIFFRACTION (1.3485 Å)